If you go back to the last page of the prior thread the actual full rejection paperwork is linked. It says in there the building is divided into three flats.
I have to say how much i also don't love the street numbering. The attic flat is 52 i assume (as Calum MacPhail's name is on the planning paperwork asking for a large dormer instead of two small to the rear). The ground floor is 53 as per the current sales schedule. So what is the first floor flat? 52 and a half? It was the vague descriptions PLUS photographs of exterior PLUS the fact that they liuve in the attic at 52 and the ground floor is 53 which had me convinced it was only a 2-dwelling building. There's no reason to it either as if you go on street view some flats in some buildings nearby are lettered, i.e. main door is 65, then there's 65a, 65b etc. and others seem to be like this, each flat gets a whole number.