Andy Hall wrote in message . ..

I am not sure which ones you mean here.

Oh you know, the extractor thingies more commonly seen in kitchens.
Vent Axia also rings a bell. Pull a cord or push a button and off they
go, commonly wall mounted. Marvellous.

- Fit roof vents which can be opened to allow the warm air to convect
out. This is very effective and also pulls in cooler air through
the door, windows or from inside the house.

Roof vents sound like just the ticket, didn't realise they could be
fitted to polycarb roofs. I assume they close, got any links for
visual examples?

Ta.