Hello. I’ve got a A3 2.0 Quattro Diesel 15 plate 5 door. Major problems with heater. It blows out cold air. Coolant is topped up to right level, it’s been drained and flushed out and refilled. The silica bags in the coolant tank are still all fine and not burst. Waters passing through the matrix all good and seems to be no blockage. I’ve had it plugged into a diagnostic test, everything all good on there. I’m based in Nottinghamshire; any one ever had the same problem or similar? Where would be best to take it to around Lincoln, Nottingham, Sheffield or Doncaster? Thanks