I get an intermittent buzzing on the Radio, but AM only - found that it Only does it when the Climate Control Fan is on

But as you know the air con won't come on then - hot work listening to TalkSport!
Any ideas ?? maybe suppress the fan or insulate the Head Unit from any interference?

Annoying but not essential, CD Changer now working perfectly, FM Crystal Clear, MP3 via cassette interface - even plays Cassettes well so not changing the head unit......
Cheers