So having had the standard extending / retracting aerial since I got the car several years ago and having been required to clean / de-salt and generally clean the blighter up I decided I was going to replace it with something a bit more subtle. The fact I have a cheap CD player in car doesn't help. Turn on the head unit and whether CD or radio is playing, the aerial is up. Queue the new mast.

Yep not very exciting but it does work and prevents the car from looking like an RC model ! I like it