Depends on the medicine dispensed, or did you mean writing a prescription that will be fulfilled elsewhere? I think last time that came up it was £40c for writing a prescription, but that was a while ago.
However, on looking at the price list online, a prescription charge is listed as £29.50, so it has improved [https://www.theneighbourhoodvet.co.uk/about-us/prices].
Nor me, I left there years ago, even though it's just round the corner from where I live.
I was at another one in between before moving to The Gardens.