Room temp at night

So I live in a new build flat so in the summer it was roasting hot! At the moment at night the bedroom is sitting at 23 so last night I decided to have the window open slightly and it dropped to about 21.5. Baby was sleeping in a babygrow and 1 tog sleep bag like the tommee tippee temperature chart suggests but her face was cold and when I checked her chest that was also cold. She also woke up at about 1am which she never does. I’ve got a 2.5 tog sleep suit, do you think I should put her in that with just a vest on underneath?