I read that you were not supposed to lay down after you eat for 2-3 hours.. Has anyone read this and do you know why ?

(I had a late dinner and I'm tired, LOL)

Haven't heard that one and I have just reread a lapband book from my surgeon's office (13 months post-op, just decided it was time to refresh.) It wasn't mentioned in there, either. Maybe it is to do with reflux?

Yes it is to do with reflux. You need to give the food sufficient time to go down as if you don't then reflux is a risk. Try not to eat so late in future! You can try going to bed and see what happens , maybe try sleeping with the head of your bed raised.