Cant help with your search but my local auto transmission specialist told me that no "specialist" will ever put your car on one of those flushing machines.
Interesting…… the one I asked said they didn’t have an adapter to fit….. what a ZF auto box,, wonder what they do work on. !!!
Perhaps my local BMW indie and standard manual method then.
Try Noel @ NCB Autokraft based in Solihull (Google his phone number). He is very good and will do a fluid and filter change for you but wont do any kind of "power flush" where the box is rinsed out.
Be aware Autokraft is in the middle of nowhere so bring a bike or cash for a Taxi to get you into civilisation otherwise you will be hanging out with sheep the most part of the day. He will need to let your car/gearbox cool down so most likely if you drop the car at 0830 he wont touch it until at least that afternoon potentially for a next day pickup depending on how busy they are but he will set your expectations.
If you need an actual transmission guy then I have been told that Transmission Technology in Knowle are very good also in the middle of no where. These are the guys you speak to if you need clutch packs or mechatronics looking at.