^^^ The final 'sauce' in my post above should have had '"white" in front of it (with all the other 'sauce' references being to the meat sauce).
I can't recall ever making lasagne but I've consumed many (both home-made by friends and bought by me from supermarket chiller cabinets) and I can't recall any problems with the bottom layer sticking. (Indeed, when I compare it to the layered bakes that I do make, such as my famous pilchard bake and my own-recipe corned beef hash bake, I think it extremely unlikely that there would be any problem).