We have 6 bikes in our 'residential dwelling', and I don't think that is too unusual?
Unfortunately it is. There are 40+ residences on my street (not in the city centre) and I've never seen anybody who lives in one of the other houses on a bike. When I lived in a block of flats in the city centre, the number of bikes/flat was about 0.5.
If the spaces are unallocated, then I can believe that 1 per flat is probably sufficient at the moment. Hopefully it won't be sufficient in the future - and the developers need to account for that.