Home insulation query (I think)

Esty76

HI, i bought my house in 2003 from new. I've had nothing b ut issues from nw on the entire corner of my house (passage where front door is downstairs loo and upstairs directly above - bedroom being cold in winter.)
I raised with builder - i was single at the time and they came and drilled outside next to front door showing me there was insulation and said a few others had complained the same so installed double radiators.
Now upstairs my daughters bedroom is so cold, when we open the door the cold comes blowing out! her room and downstairs develops mould and damp i have to keep on top of. 
My husband has re pointed (hes a pointer) under her window as it had dropped out. we've checked loft insulation is right up to edge and checked guttering isn't full of leaves and then snow today.
But then tonight my daughters room literally leaking in and blebbed her paint. So is  this a insulation issue? Can we just get an injection or something? I mean its blowing cold air in like shes sleeping in an open air room?
I always thought when they drilled showing me insulation it was at door bell height, but how do i know it went all the way up?
I dunno if i can claim for this - insurance - or even what this is?