[Nickthedentist]

Plessey version (PBT111) here too: https://www.ebay.co.uk/itm/Plessey-B...IAAOSw6Mldg~Eh

The type I referred to in post 22.

And on Bob's site:
https://www.britishtelephones.com/pbt100.htm and
https://www.britishtelephones.com/pbt400.htm

N.