Room Temperature

I roll the edge of the baby grow over my babies hands. It's just the hands are exposed and not moving when she's sleeping. I dress my baby the exact same in the same temp room. She's always got cold hands. I was always told to not worry if their hands feel cold but judge it by chest and neck like you've been doing :).
If I curl the edges over on her baby grow her hands are fine.

I've compared the gro egg to house thermostats in my home and my mum's and they're always pretty much the same so they are accurate.

if chest and neck are fine they don't need more layers, just cover her hands :)

Have you got a lighter bag? Then you could use more layers. Mine is in long sleeve vest, baby grow and 1.5tog bag. If he has a short vest on he's freezing all the way up his arms.

We are still using a long sleeve vest for 18 we use a 3.5 tog sleeper if its bellow 18 at bedtime as pur room drops to 13/14 over night. If our room is already around 16 I will put the sleeves on the 3.5 sleeper as I knows going to get really cold like 11/12

I dress my 4 month old exactly the same as you and his arms/hands are always cold but he doesn’t seem bothered by it. As long as chest/neck is fine I’d say continue what your doing x