Our existing fan is old, inefficient and extremely loud. I believe it is an old P Series centrifugal extractor made by Greenwood Airvac, although I am unable to be certain as the model and serial numbers have both faded to the point that they are unreadable. A picture of the unit without its cover is included below:
I have found a model I would like to replace it with - an ST100B Silent Tornado Hi-Power Bathroom Fan, but I don't understand enough to know whether it will be possible to easily replace one with the other. For example, do they require different diameter venting holes?
I intend to employ an electrician to do the actual work, so I do not require any detail beyond whether the model I have chosen is a suitable and easy to install replacement.