Cold Room Insulation

[Corry]

Hi - Looking for some help.
 

Our dormer window bedroom is cold with the walls in the pics being very cold. After removing the plasterboard, this is what is behind. A mixture of loft insulation stuffed into the RSJ and Kingspan.

Should I use expanding foam in the small gaps you can see or just tape them up? Will doing this make a difference to the room temp?

Does this insulation meet building standards?

Cheers.