https://goodweeplace.com
On the face of it, who doesn't want venues to treat trans people - or indeed anyone - with respect and dignity? No problem with that.
But it would seem from the 'advice' pages that this might be places that are willing to turn a blind eye to people breaking the law, or even be happy to quietly break the law themselves.
Handily, there's a map of all the places signed up to this. Definitely something to keep an eye on.