What kind of a house was Bosinney building for Soames in Robin Hill? The first chapters suggest that it was out of the ordinary, more modern than what was currently being built. Perhaps, in the style espoused by Lutyens or Mackintosh just a shade later. Here are some links to houses that might be like the one Bosinney is building:

Hillhouse - Charles Rennie Mackintosh

Bellahouston Park - Mackintosh - I think this is particularly interesting, as it was built for an art lover.

Greywalls - Edwin Lutyens

Heathcote - Lutyens