Thank you all again.
I got it working now using javascript:history.go(-1)
Utter newb question: how come javascript:history.go(-1) works?
I know I have java components installed on my PC but don't know anything about it; is that where is gets the code for history.go from?

I have Xara Web Designer 6, I don't think I can create custom buttons with my version.
What version do I need to do that with?

Re back button vs browser back button.
When you are clicking away in a large web site I think it is cosy to keep clicking within the web pages.
Just my personal feeling.