Thanks for your suggestions toltec
In the photo persona when I can see the image that I am working on only 'Dock Tools' is checked (but greyed out) and 'Hide Studio' is checked. If I then select any of the above or uncheck 'Hide Studio' then the image immediately disappear. I can then continue to check all the above and uncheck 'Hide Studio' and all these are available but the only view of the image I can see is the small one in the Studio. If I then toggle the User Interface the image appears but all the above are now unchecked and the Studio is hidden.
I tried your suggestion and reset everything (I am new to Photo so did not lose much) but this did not fix the problem. A reboot of the PC is one of the first things that I tried, without luck.
Howard