Gary tbh a Hobb's Bankers rings a distant bell with me too, although I have to admit I can't really remember seeing anything I do recall mention of it here and there and also on the net.

A quick look at safeman's website shows reference to a Hobb's Hart Bankers but can't see mention of a Hobb's or Hobb's Hart Branch Bank, so it seems a bit reversed from what's in the Tann guide which lists the Branch Bank but no Bankers, under Hobbs or Hobb's Hart.
Saying that though the Hobb's listing in the Tann guide does seem pretty odd with the Progress C's grouped with the E's in the grade above the D's...

Interested to know what you dig out from your old literature, unfortunately what little I've got is mostly 1960s onwards.

cheers, Huw