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Water companies must fit meters for free on request unless it's justifiably impractical, such as flats with shared pipes. You can complain to Ofwat is they refuse.
They will fit them inside or outside in the street but to do it they have to be able to turn off the supply to your dwelling, hence they need a working isolation valve on the supply.
Won't be quick though. A few weeks for the booking.
Have you got a water meter yet? Ask them to fit one and they will have to sort out the external stop tap as part of the job.