Jackman
I use grobags too - they are fantastic. I think a good temperature is about 19/20C. Im sure when the room was 17C, DS woke up a lot more, and was more active in bed - maybe to try to keep warm. DS loves sleeping on his tummy/side, so i cant tuck him in anymore, hence why the grobags are great.
I have a thermometer on the wall, and i try to keep the room at about 20C. In summer, its very difficult to keep it that cold, it sometimes gets up to 24-26C, which is not ideal. As sianie said, i just sleep him in less with a very thin grobag.