I am guessing a heater matrix leak with it being in that area, assuming the matrix is in the same place as the mk3/4 escort.

Quick fix is to join the 2 pipes that run from nthe engine bay through the bulkhead, this will in effect isolate the matrix from the cooling system but you will be blooming cold!

PS looks like your coolant is rusty and has no/very little antifreeze in it, you are asking for a popped core plug/cracked block at the worse. Best drain the rad/engine untilyou get round to fixing it or the weather picks up.