if cash machines go, post office branches go and banks go. where else would people draw out from 
maybe that is a discussion for another thread on another day
Cash machines will always be there, supermarkets have them and there's still one local to me near where one of the post offices was.
"So there will still be the same amount of post office branches in the uk" there's two less that I know of and that's just near me.
The one that was nearest to me was a stand alone post office shop but it closed as all payments of pensions etc moved to online, it then opened in a newsagents further up the street but moved from there to the small supermarket a couple of doors along then closed altogether.
In that small group of shops there are still 2 pizza shops, 2 Indian takeaway shops, a burger bar, a Chinese takeaway, a Subway, a sandwich/pie shop and a pub. No bank or post office though a cash machine is still there.