The mystery to me is that after his bath and bottle at 7ish he goes down without a fuss - I put him down awake and he drifts off without a fuss.
It may be that he is so tired by the end of the day he is having that bottle more relaxed and taking in less wind? I know with our DS when he was about this age and developed reflux he was i na lot of pain and napped horribly in the day, but at night he started STTN and if he had a feed in the night he didn't seem to get the pain as bad (he would fall asleep upright on me though) When I discussed this with plunket and the Dr they both said he was probably so shattered during the day he would crash at night.