Thanks for the suggestion to look at street view - it's a street of ordinary 1930's houses, some of which have been extended in various, fairly conventional ways, with the exception of this one and it's similarly extended next door neighbour.
It's a one bedroom apartment with three bathrooms - the blue bedroom is either a CGI impression of what it could look like or it's a picture of what the same thing looks like in the house next door. The pictures of the bed on the mezzanine are unlikely to pass building regulations - fire doors, roof height, and therefore I can't see how it could be classified as a bedroom....
The use of Jack and Jill goes against convention as this usually refers to a single bathroom with two entrances, usually shared between 2 bedrooms. In some cases in the text, I think he means (yes I am assuming his gender), his and her's (again genders assumed)
The house is not built around the tree - they had to 'work around it' not 'build around it'.
However... further wasting time on the internet made me look closer at next door's garden - clearly the 'more is more' concept applied there too... I think this one bedroom bungalow is at the bottom...
www.bristolpost.co.uk/news/bristol-news/lime-green-home-hot-tub-4328670
It would be interesting to know what the 'the long planning history associated with the site and the level of public interest that has been generated over recent years, including from the local ward councillors.'
Did they snap up 2 pretty average 1930's detached houses - turn one into 4 flats selling for a total of £1.6M in 2018.. nethouseprices.com/house-prices/bs92pw plus the garden bungalow and the second one into two or more flats..
If this is all true... then the average buyer is clearly just not inventive enough in terms of what can be done to houses to increase their value, get round planning restrictions and get buyers to pay inflated prices based on unique fixtures.... . we are underestimating this person's genius.