Hi - can anyone recommend what extractor fan would be best for a bathroom with no external walls or windows - basically it's in the middle of the house. Very small bathroom and currently has a celiing extractor fan with a length of duct leading to the outside / an air vent near the facia boards but it's pretty useless. The fan does work and the duct is all clear / connected properly it just doesn't seem to do a great job.

Thanks - J.