I love themed houses which are based on an era - the 30's, Victorian etc. House themed houses!
This is just annoying. And what is that mezzanine for exactly? It buys you zero separation from the living area.
The listing is very pleased with itself, but it will take a hell of a niche buyer to pick it. You have to want EXACTLY THAT - and someone with a £1.5m budget who doesn't want EXACTLY THAT will be able to buy any other house and make it what they like.
So they either need a buyer with the money who loves it as is, or a buyer who loves the potential of the space AND can afford to gut it and start again.