Centrifugal

Try something like this,4" in line fan. Iv fitted a few without problems and great results.
There are various different makes along the same idea, any of the wee cheap 4" fans are a waste of time.

 

There's plenty out there to chose from. Centrifugal are good for moving air over distance through ducting/ soil pipe.

 

Id need one attached to my arse, dodgy crab claws consumed and now feeling decidedly like im pishing out of the wrong orifice.

 

Rather you than me if he's pishing out of it, but good luck Carr

 

Way too fast! You should focus your talent on Word Association!

 

Depends on size of room and what type of air you want to shift, steam/ cooking.
Mid duct fans are good, because of their position you can 'hide' them which makes for vert quiet running.
Expelair are a good brand name with fans for all situations.

 

Fitted many various extractors over the years but haven’t fitted an ‘in line’ one.
Have you thought of fitting one in the attic using 4” ducting from the ensuite ceiling to a vented roof tile or exterior wall?
Wiring would be easy as you could pick up the permanent live and switch needed from the ceiling rose/ light fitting.
A visit to your local electrical stockists would help with the size of extractor needed.