Hi, DD is now in her 2.5tog gro-bags. On the gro website, it says for temps of 18 celsius to wear a long sleeve body suit and pj top, for 20 cel a long sleeve body suit...and for 16, a sleep suit over bodysuit. Our room is between 18 - 19. I had her in a sleep suit, with the gro bag...but she felt a bit warm, so changed her to just a long sleeve body suit (which I presume is a vest with long sleeves?) Does this sound ok? Would a sleep suit be better? She just felt a bit warm... What does your LO wear under a 2.5 tog and at what temp? Thanks!