Just taken my fastback out for a run and it was a little chilly so I put the heater on. It's the first time the heater has been properly used in 33 years. After a while I started to feel a little light headed so I guess I need new heat exchangers!
The question is where is the best place to source a new pair (in the UK preferrably), I looked at Heritage Parts but they want £309 a side

, any suggestions?
Thanks