Post office names
Back when my Dad was a Head Postmaster in the 1950s, there was a government organisation called "The General Post Office". It was a blanket organisation for
* Royal Mail (who delivered Letters and Parcels)
* Post Office Telephones (landline phone provider
* The marine radio stations (Portishead, North Foreland etc.)
* Martlesham research station
* The railway telephone branch (not the same as Beritish Railway signalling division)
* Post Office Telegram services
* National Savings
* Post Office savings bank (both deposit schemes, not money transfer systems)
* Post offices were the retail outlet for mail, for the payment of social benefits like child benefit & the old age pension and the handling of driving licences and car taxes. You could pay your income tax there and buy national insurance "stamps".
Later the government invented the Giro bank, a publically owned clearing bank which used post office counters for public access.
Nowadays we have
* Post Office counters Ltd - the retail operation, including foreign currency, the two saving schemes, and a sort of bank. They still do car tax and driving licences, and pay pensions to people with magnetic cards and no bank account.
* Royal Mail, who deliver letters
* Royal Mail parcels, who deliver broken things in crushed boxes
and that's about it. All the other stuff has been sold off, and they want to sell off those 3 too.