Thalia--Feral cats with Turkey breath may be the ticket. I think the eating in her sleep story is weak and may not fool Ceylon. Can you not suck up to the mastiff and enlist Grendel as a personal protection Mastiff? Surely Ceylon does not have that noble breed cowed? Besides a woman of your stature should have an entourage and I think one mastiff cross might qualify as an entourage.
Thalia-You must remember one thing about turkey, it makes you VERY sleeply after you eat it. So the proof as to who really ate it is by who is the MOST sleepy!! So try very hard to ALWAYS be awake and IF Ceylon is sleepy MAYBE she is the one that ate it!