repeating item in header won't stay still

[CK21]

Xara WebDesigner 12 Premium - sorry about spelling mistake - Repeating Item in Header

I'm in the process of transferring an existing website from another software to Xara, which I know and like and on the whole all is going well. But ... at each end of the header is a picture. The one on the left stays where it should on every page, but the right one will be out of line (a little lower than the header's bottom line usually) on every page - not necessarily in the same place on each page - just not where it should be, which is sitting in the bottom right hand corner of the header. I have tried 'position on page', both Fixed and Automatic, but obviously not the right answer. This has been going on frustratingly for a long time and at last I realise that there is a forum which might help.

We are not technical experts, although have run amateur websites for many years. I'm 'medium simple experienced' with Xara, and my husband more so on his own website, but we don't know what to try next for this. It does however remind us of a Navbar we were doing a few years ago on another site (predecessor of Xara) which kept moving around in the same way until we discovered that we had to - as it were - build the website round the Navbar, because that was the fixture and wasn't going to be movable. I suspect that something of the sort is going on here, but am not technical enough to know how to deal with it. (To be clear - no problems with the Navbar on this site - just the header.)

I'm happy to admit that I am stupid, but I can do a lot of useful things on websites - until I come up against something that I obviously don't understand. And unfortunately although we solved the Navbar problem I described above, I can't remember how.

I wonder if anyone can see how stupid I'm being?