In reply to my post of last night, I think it must have been the wine talking.
I have spent the morning working on Robert Darwin adding and editting details and census entries. Everything works fine. I can detach the tab to overlay it onto a census image and transcribe from one to another just as I used to do with a popup window. The look and feel of the whole process is elegant and I would be happy to see this released. I have just gone back to my existing site to add a 1911 census entry to see which way I prefer … and the answer to that is your new way.