Sugar soap seems to be the UK equivalent of TSP in the USA, however they're formulated slightly differently.

Thanks for the advice, I started scraping off the bubbles to patch (while the wall was slightly wet still from cleaning) and found the top layers of paint came off very easily even where there weren't bubbles. It looks like the best option is to scrape all the paint off back to a layer that is adhered properly.

Thanks for the suggestion. I just did the X test, the edges of the score came away slightly during scoring which the tape then removed, less than 1mm though.

The adhesion of the old paint seems to be the problem, I washed a new section and attempted to scrape off the bubbles as they appeared... While doing this a whole section of the paint came away, revealing a layer of blue paint. The blue paint seems to have adhered properly so it looks like the best option is to strip the whole wall of the top layers of paint