Ok so my new problem this week to add insult to last week's injury!!
The heater will only blow cool air ! Any clues? I got a fault reading on display of if 22 or something?

 

cold air normally points to a faulty thermostat

but you could have an air flap issue where it's got stuck on cold only

sometimes there is a reset you can do via the buttons without having to take it all apart and push the stuck rod but i'm not that clued up on the mk4's

 

Ok I'll try and find reset thanks it's going into garage Thursday so fingers crossed. I have a 32 year old xr3i that manages to produce heat with no gimmicks lol!