Thing is that on the face of it, its a good idea,
But cut out the entire commercial market, and your left with domestic.
Now again on the face of it still not a bad idea, when you consider, alot of new builds are three storey so like mine have three toilets and three extractors.
But the missus hit the nail on the head when she pointed out that with a toilet and basin this toilet extractor is all you need.
But.
My ground floor has a toilet and basin, so this would be fine.
My mid floor also has a bath and no windows like most three storeys, so it needs a ceiling / wall extrator anyay so the toilet one would be an extra not replacement.
My top floor has a shower and no window so again ceiling / wall extractor is needed, so again this would be an extra to a fan not a replacement.
So your already down to a third only.
Coupled with the fact that the builders will buy huge quantitys of the extractors, and will be getting them cheap anyway.
Your probably out of the new build market two, leaving the market as basically what they came up with, toilet under stairs, this must be a small, small market.
If only they had gone in with a more powerfull version, for the commercial purposes then it would have been a different ball game.