I am designing a vf page to book people onto different events that we run.
The page has a rows asking for name, phone etc and the event that they want to be booked on.
Once the user presses save it adds the list of new records (Event_Delegates__c).

It all works fine and does what I need it to do apart from one thing. When I add a row into the table it resets the venuex SelectList and clears the information. I am not sure where the issue is in the code.

Page:

<apex:page sideBar="false" controller="BookEventsTest">
<style>
        .homeTab .pageTitleIcon, .individualPalette .homeBlock .pageTitleIcon
        {
            background-position: initial;
            background-image: url('/img/icon/profile32.png');
        }
        .dateFormat{
            display: none;
        }
</style>
    <script>
    function updatehidden() {
        var sellist = document.querySelectorAll("[data-sellist]"),
            inpfield = document.querySelectorAll("[data-inpfield]"),
            inpnew = document.querySelectorAll("[data-inpnew]"),

            for (var i = 0; i < inpfield.length; i++)
              {
              inpnew[i].value = sellist[i].value + ' - ' + inpfield[i].value;       
              }
            }
            
    function setvenue() {
            var venue = document.querySelectorAll("[data-venue]"),
                venuenew = document.querySelectorAll("[data-venuenew]"),
                datenew = document.querySelectorAll("[data-datenew]");
                
                for (var i = 0; i < inpfield.length; i++)
              {
              venuenew[i].value = venue[i].value.substring(11,255);
              datenew[i].value = venue[i].value.substring(0,8);        
              }
    }
</script>
    <apex:form >
        <apex:variable var="rowNum" value="{!0}"/>
        <apex:pageBlock >            
            <apex:sectionHeader subtitle="Add Event Delegates"/>
            <apex:variable var="rowNum" value="{!0}"/>
            <apex:pageBlockTable value="{!DelegateList}" var="del" style="width:100%">
                <apex:facet name="footer">
                    <apex:commandLink value="Add" action="{!insertDelRow}"/>
                </apex:facet>
                <apex:column headerValue="Name" style="width:10%">
                    <apex:inputField style="width:98%" value="{!del.Name__c}" id="inpfield" required="true" html-data-inpfield="1" onchange="updatehidden()"/>
                </apex:column>
                <apex:column headerValue="Phone" style="width:10%">
                    <apex:inputField style="width:98%" value="{!del.Phone__c}" onchange="updatehidden()" id="phone"/>
                </apex:column>  
                <apex:column headerValue="Email" style="width:12%">
                    <apex:inputField style="width:98%" value="{!del.Email_Address__c}" onchange="updatehidden()" id="email" required="true"/>
                </apex:column>
                <apex:column headerValue="Job Role" style="width:10%">
                    <apex:inputField style="width:98%" value="{!del.Job_Role__c}" onchange="updatehidden()" id="jobrole"/>
                </apex:column>
                <apex:column headerValue="Company Name" style="width:12%">
                    <apex:inputField style="width:85%" value="{!del.Company_Name__c}" id="companyname" onchange="updatehidden()" required="true"/>
                </apex:column>
                <apex:column headerValue="Event Type" style="width:11%">
                <apex:actionRegion >
                <apex:selectList style="width:98%" value="{!selectedType}" multiselect="false" html-data-sellist="1" size="1" id="sellist">
                <apex:selectOption itemValue="Type1" itemLabel="Type1"/>
                <apex:selectOption itemValue="Type2" itemLabel="Type2"/>
                <apex:selectOption itemValue="Type3" itemLabel="Type3"/>
                <apex:actionSupport event="onchange" reRender="venue"/>
                </apex:selectList>
                </apex:actionRegion>
                </apex:column>
                <apex:column headerValue="Venue" style="width:20%">
                    <apex:selectList value="{!venuex}" style="width:98%" html-data-venue="1" size="1" id="venue" onchange="setvenue()">
                        <apex:selectOptions value="{!venues}"/>
                    </apex:selectList>
                </apex:column>
                <apex:column headerValue="FOC?">
                    <apex:inputcheckbox value="{!del.FOC__c}" onchange="updatehidden()" id="foc"/>
                </apex:column>
                <apex:column headerValue="Delete" style="width:3%">
                    <apex:commandLink style="font-size:15px; font-weight:bold; padding-left:30%; color:red;" value="X" action="{!delDelRow}" immediate="true">
                        <apex:param value="{!rowNum}" name="index"/>
                    </apex:commandLink>
                    <apex:variable var="rowNum" value="{!rowNum+1}"/>
                    <apex:inputHidden value="{!del.Name}" html-data-inpnew="1" id="inpnew"/>
                    <apex:inputHidden value="{!del.Event_Date__c}" html-data-datenew="1" id="datenew"/>
                    <apex:inputHidden value="{!del.Venue__c}" html-data-venuenew="1" id="venuenew"/>
                </apex:column>
            </apex:pageBlockTable>
            <br/>
            <apex:pageBlockButtons location="bottom">
                <apex:commandButton value="Save" action="{!insertDelegates}"/>
                <apex:commandButton value="Back" action="{!cancelDelegates}" immediate="true"/>
            </apex:pageBlockButtons>
        </apex:pageBlock>
    </apex:form>
</apex:page>

Controller:

public class BookEventsTest {
    
    public List<Event_Delegates__c> DelegateList {get;set;}
    public Integer rowNum{get;set;}
    public String selectedType{get;set;}
    public String venuex{get;set;}
    
    //Add initial Delegate row
    {
        selectedType = 'Type1';
        venuex = '';
        DelegateList = new List<Event_Delegates__c>();
        DelegateList.add(new Event_Delegates__c());
    }
    
    //Insert DelegateList and redirect
	public PageReference insertDelegates(){
        insert DelegateList;
		PageReference reRender = new PageReference('/');
		reRender.setRedirect(true);
		return reRender;
    }
    
	//Cancel Delegate and redirect page
    public PageReference cancelDelegates(){
        PageReference reRender = new PageReference('/');
        reRender.setRedirect(true);
        return reRender;
    }
    
    //Insert Delegate Row
    public void insertdelRow(){
        if(DelegateList.Size()>0){
        Event_Delegates__c tmpdel = DelegateList.get(0);
        DelegateList.add(new Event_Delegates__c(
                                             phone__c=tmpdel.phone__c,
            								 email_address__c=tmpdel.email_address__c,
            								 company_name__c=tmpdel.Company_Name__c,
            								 venue__c=tmpdel.venue__c
                                            ));
    }
        
        else DelegateList.add(new Event_Delegates__c());
    }
    
    //Delete Delegate Row
    public void delDelRow(){
        rowNum = Integer.valueOf(apexpages.currentpage().getparameters().get('index'));
        DelegateList.remove(rowNum);
    }
    
    //Display correct picklist depending on selectType
    public List<SelectOption> getVenues(){
       
       List<SelectOption> venueoptions = new List<SelectOption>();
       
        if(selectedType=='Type1'){
            Schema.DescribeFieldResult fieldResult = Event_Delegates__c.type1__c.getDescribe();
            List<Schema.PicklistEntry> venues = fieldResult.getPicklistValues();
            for( Schema.PicklistEntry v : venues)
       		{
           	venueoptions.add(new SelectOption(v.getLabel(), v.getValue()));
       		}          
        }
        else if(selectedType=='Type2'){
            Schema.DescribeFieldResult fieldResult = Event_Delegates__c.type2__c.getDescribe();
            List<Schema.PicklistEntry> venues = fieldResult.getPicklistValues();
            for( Schema.PicklistEntry v : venues)
       		{
           	venueoptions.add(new SelectOption(v.getLabel(), v.getValue()));
       		}
        }
        else if(selectedType=='Type3'){
            Schema.DescribeFieldResult fieldResult = Event_Delegates__c.type3__c.getDescribe();
            List<Schema.PicklistEntry> venues = fieldResult.getPicklistValues();
            for( Schema.PicklistEntry v : venues)
       		{
           	venueoptions.add(new SelectOption(v.getLabel(), v.getValue()));
       		}
        }
        else{}
       
       return venueoptions;
       
       }
}

If someone could give me some pointers it would be really helpful,
Thanks​​