"And one of these wind driven extractors for ventilation:
http://convertavanltd.co.uk/services/van-ventilation.php"

Has any one used one of the Flettner wind extracting vents before?
http://www.flettner.co.uk/flettner_2000.htm

Can you turn if 'off' so to speak? Does it suck in loads of dust?

I'm primarily interested for when the vehicle is parked up - will it work or does it requite a decent wind to be even half useful?

I wouldn't mind fitting one of the side of the landy as well to cover a previous hole if it would work....

Um, if it extracts, then it doesn't suck in dust, as it's an extractor.

Air from inside of the vehicle gets extracted out of the vehicle. If there's no wind they don't do much, that is, when you're stationary... When you're driving they of course 'always' work...

No need to turn it off!

you're welcome to view my converted van
 

Matt,
Sorry I missed your original post, was away on holiday. I have converted a citroen dispatch into a camper. You can squeeze in if you're very careful...
35 litre compressor fridge, 110a second battery, 2 burner gas hob, 4.5kg calor bottle, porta potty and an eberspacher diesel heater while still having space for a double bed.
I live in Hamilton only a few miles from you so you are welcome to come and have a look at the van if you like.
Drop me an e-mail to sdwebmail[attt]yahoo[dottt]co[dottt]uk

cheers

Stewart aka jethro