Aye tis indeed, just make sure you dont drill into the roof strengtheners. You would be in trouble then. Pull the head lining down a bit along the back and see were they are on the roof skin.
I just use a BFO Mag-mount, and put it right in the centre of the roof. Don't seem to get many problems with the wire going through the door and door seal!
i did cinsider that but want to leave it on permanently it's only for green laning and pay&play day's so it'll have one of those rubber aerials they have about 2-3 mile raduis wich is plenty and there small was thinking of using one of these psm1 mounts just to the right of the rear door.