I'm investigating.
For me, its the extension which is worst, but it is a fair way from where a PIV could be installed in the loft. Is such a thing still going to be effective for a cold damp extension?
Assuming the extension is ground floor only then on a two story house?
Should be fine as long as the house isn't huge. The units come with different speed settings so match size of home/levels of condensation. Best to contact Nuaire prior on square footage involved etc.
On a side note, I see they are doing a flatmaster range now too which may be worth a look for the OP.