I know how to get the rear door cards off and i want to check the Ariel amp because the reception is rubbish. (head unit is alpine which has made some difference to the reception.

Anyway, I think its under the rear pillar so how easy or difficult it is to remove ? Anyone got any pics or howto's ? or even a way of checking that the amp is working with it in situ ?

Yes rear passenger side up near the top of ths side window. Just check if it is getting power when the radio is on. Nothing much else you can do I don't think

If you check the how to guides you will find antannae boosting link..

anyway this is the link

http://www.bugone.co.uk/fiat/antenna_booster.htm