Here are the Prince Renegade squash shoes.
I’ve only seen the all-black one above available in the UK.
Over in the States they have this blue guy, called the Renegade LS:
There’s another shoe that looks pretty cool called the Prince Renegade 2 LS. This is marketed as a tennis shoe but it has non-marking soles so it could be used for squash.
Buy (US): amazon.com