[Nocturnum]

Well, after having read the replies I cunningly figured out what my problem was - my brother-in-law and his son came around yesterday and were playing the game - on easy settings. No take-offs!
Aaaaaaaaaaaarrrgghhh. I must have spent 2 hours trying to work outwhat was going on.
The map and my installation are clearly fine. What a pain in the arse.