Ahh..
Yeap, in mine there is a gap between walls and roof. I think the "seal" could be improved but I haven't bothered (too hard basket). The air movement is in theory good for reducing condensation, although I still have huge problems with condensation.
Plenty of pics on my website...
http://www.rogergroom.com/rogergroom...y.jsp?Item=185
Happy to help with more explanation, but the pictures will probably answer it all.
Roger.