I can happily report that I am once again getting eggs! Like you, Madamjojo, my egg eater loved the mustard I put in a shell. Having definitely identified her, and as a result, putting her into solitary seems to have regained the status quo.

So that I can eventually re establish her into the flock, I am currently trying to design and build a roll away nest box. Any ideas how to do it will be apreciated.

Thanks for all the helpful hints and Janeyo, thanks for the link you sent me. Very useful.