Thanks for the responses.
I think the problem I had was that when I did CTRL Click on an object, the script showed xfa.resolvedNode instead of xfa.form.ResolveNode.
This meant I had tended to use either of the below means to reference objects in the majority of my scrips: xfa.form.Form.Form.sYourDetails.sFirstName.vFirstName
Using these I couldn't reference a specific instance or dynamically reference the objet name because I wasn't using resolveNode(s). I new I needed to us it, but it wasn't evaluating as mentioned above.
1. Why fo I need to reference the form dom in the resolveNode Expression?
2. Why wasn;t designer doing this by default?