When I worked at Bart's Hospital in the 1970s, there was a semi-retired physician of the old school who would occasionally prescribe leeches. The hospital pharmacist (firmly based in the 20th century) refused to stock them, but would call a semi-retired pharmacist at another London hospital who did stock them to send some over.
My understanding of the current use of leeches is that because they only remove a small amount of blood, they are very useful for localized removal, mainly in "cosmetic" surgery, to minimize scarring.