On 4 Aug, 08:50, sm_jamieson wrote:

Access to the fan for maintenance might be interesting though. The fan
would be in a small loft area in a single storey extension ceiling !
Simon.

could you maybe mount the fan(s) outside?

stick a velux or two in the roof - left open on "vent" in summer?
stand on a chair you can reach 10ft......

Cheers
Jim K