The head gasket was changed on this car,the heater worked before it was changed.

I used 2 packs of "C-Lit" in the rad prior to the head gasket change. the system has been bled at the temp.sender unit as advised in the manual.

The engine temperature is fine,and the rad.fan kicks in when it is supposed to.

The heater fan works on all speeds,but when it is placed on the windscreen no air is coming out of the vents.

I changed the radio on it,but the co-axial cable was very short,and slipped inside the dash,

I had to pull it to get enough length to fit it in the radio.I am wondering if I may have dislodged the vent connecting rods.

Any ideas? apart from my knees knocking in this weather,the windscreen will not demist.