Given that they may have been fitted when water was supplied by different councils, then authorities, then companies over a period of several decades, I think they may be similar but not identical.
And, they do belong to your water supplier....and they don't like consumers fiddling with them.
i'm not on a meter, but i have a water meter in the pavement with the stop cock. I pay a monthly fee regardless how much i use, then if they check the reading and it's over i'm in dept :D Check it and it's under they may owe me some ££ so they try to work out the average precisely
I have to agree with hc....spath IS on a metered supply. The fact that readings are taken and billing adjustments made, confirms this.
If the supply was unmetered (ie a fixed rate based on rateable-value), you would simply pay a one-off yearly or two twice-yearly or monthly fixed amount.....no readings necessary and no billing adjustments made.
However older, non-metered, stopcocks tend to need a big stopcock key to turn the water on and off. The fittings do vary slightly but you can buy 'combination' or 'universal' keys. This one, for example, is suitable 'for 1/2" and 3/4" crutch head and 1/2", 5/8" and 3/4" square head spindle stop cocks":
https://www.bes.co.uk/universal-5-in-1-stop-cock-key-42-23213
^^^ . . . except, of course, the newer hex key type that I've got. (However, to the best of my knowledge, they're solely associated with meters, so that should be irrelevant in your case)