was looking at this chart on the grobag web site
www.gro-group.co.uk/sizes-togs-and-what-to-wear/
as I cant decide btw a 1 and 2.5 tog one. Its odd they haven't said you could use a vest and sleepsuit with a 1 tog one at lower temps.
Also I only have one long sleeved body suit and don't want to buy more as the bag is expensive anyway.
I am totally paranoid about room temps and number of layers!