What should 7 month old wear tonight to bed? It's 25degrees in her room

[RizzleBizzle]

Just wondering the general consensus here ase and DP have different ideas

My 9.5 month DS is just wearing a nappy and a vest. It gets cold later on so I sneak in and tuck a blanket round 2am ish.

vest, nappy, sheet and a fan (this was DS last night)
Switched fan off before I went to bed, then about 4am, pulled duvet over his legs

short sleeved vest and 1 tog sleeping bag. 23 degrees.