We had a compact phone in the 60s (same time the WE trimline was out...60s) it was called the GPO (Now BT) trimphone.
Looked like this (pic bellow)...It had a buzzer for the ringer which made the infamour cricket sound to the ring, as apose to the regular 700 series GPO telephones woth the...
The Telephone
"looks suspiciously like a U.S. Western Electric Slim-line. (Where is Alex from the Vacuum Forum?)"
Hyacinth's Pear white telephone was a British Telecom (BT) Minstrel phone, the first phone to have last number redial I believe.
Here is a little info on it for all interested...