I had a water meter fitted a few years ago and it was put in the house
'under the kitchen sink' next to the internal stoptap.
They then fitted an 'outreader' on an outside wall in the back garden
so they don't have to gain access to the house (I do have to leave the
side gate unlocked, unfortunately).

That was also the practice of Thames Water and what we had done. But
they no longer do so because the remote reading pads they used are
unreliable and are no longer made. They also have trouble sourcing the
hand-held readers. And the meter readers often leave the readers at
home because they are heavy. So Thames are no fitting meters externally
wherever possible - usually where the stopcock is located. The OP's
supplier may of course have a different practice (and yours may have a
source of better gear).
--
R