I will be visiting London for a week and I see so much sploshing coming out of the UK over the years - anyone have a pro tip for finding a list of doms / mistresses / folks I could pay for a messy session? DMs welcome as well!

Yeah there are tons of dommes in London, and I've met several that love WAM.

Adreena Angela is one of my favorites, and she loves WAM.
https://www.mistressadreena.co.uk/submit

Goddess Anastaxia is also really fun. She travels around a lot but used to be based in London.
http://goddessdominatrixlondon.com/

Mistress Terra was also OK, but not as fun as Adreena.
https://www.mistressterra.net/blog/

There are a lot of sites that you can check out to find them, and Fetlife is also a good place to find them if you join the right groups and do the right searches
https://www.mistresses-of-london.com/mistresses-of-london

https://www.mistress-directory.com/london/

https://london-mistresses.co.uk/home/page/3/

Lots of dommes also advertise on session wrestling sites:
https://www.sessiongirls.com/wrestlers/country/United%20Kingdom?page_num=1
https://www.wb270.com/travelEur.htm
https://www.thesubmissionroom.co.uk/

I think WAM_Traveler has covered most things but I have 2 recommendations.

1. Miss Kitty Bliss - https://misskittybliss.co.uk/ - I sessioned with her a few years ago when I was visiting London as I knew she had an interest in WAM since she has posted clips/runs a store on this site. (https://messy-princess.umd.net/) I was very much a newbie both to WAM and kink in general and she was very understanding and guided me through things in a very comfortable way

2. Mistress Bliss (No they are not the same person as above ) - https://www.mistressbliss.co.uk/ - I sessioned with her the last time I was in London in Late 2019 and I still think back to this nearly 2 years later. I've never felt a feeling of fear, pleasure and safety all at the same time to the same extent as when I was with her. Despite still very much being a novice she took great care to make sure I always felt safe despite pushing me past some of my limits. I don't know if she has any experience/interest in WAM but I would highly recommend getting in touch and asking.

Exactly what I was looking for, thank you!!

I don't know if she is still active but she always had a great time doing Sploshing https://www.ladyisabella.co.uk/services.html