The name is a pun on the fashion term "prêt-à-porter" which is often used in English. See https://www.net-a-porter.com/ for another example of a brand that riffs on the term without being French.
I wanted to say the same. I will add that because "prêt-à-porter" is a fashion term, it would be somewhat familiar to London city office workers, especially the upscale demographic they target with their prices and marketing.
The name is a pun on the fashion term "prêt-à-porter" which is often used in English. See https://www.net-a-porter.com/ for another example of a brand that riffs on the term without being French.