I don't know, I imagine would depend on the individual ready meal and how it was made up in the factory, some are made up of uncooked ingredients and some are already cooked, have got a friend who is a manager in one of the factories that supply M&S with their ready meals. Will ask him next week if I remember.
If you make bolognaise yourself then that will be fine in the freezer until whenever you find it again on a mining expedition! [emoticon with miners helmet and pickaxe]