New Post Office Banking Hub appeared on the corner here.

https://www.postoffice.co.uk/branch-finder/0061069/ampthill-banking-hub

But it's difficult to find an authoritative source of info on which bank is open on which day.

So, here it is:

Monday: NatWest
Tuesday: Barclays
Wednesday: Santander
Thursday: Lloyds Bank
Friday: HSBC UK

I visited in person to find out.