Liz, I would definitely try a shorter day, and try to include the things he seems to cope well with. IMO 6 hours is a long day for a little one if he just wants his mummy to come back IYKWIM? 6 hours feels like an eternity to them! (Not to us though hehe). If it's a shorter day, at least for a bit, he mightn't feel that it's so long without mummy, and be more reassured that you're coming back for him.

It sounds as though he will adjust fairly soon, as he really does want to like it. Let us know how it goes! Lots for me to learn in here