Buzby - the talking cartoon bird, voiced by Bernard Cribbins, was launched c. 1977 and was around well into the 1980s. Buzby's catchphrase was: "Make someone happy with a phone call."
Round where I lived, few people had telephones at home in the 1970s and making phone calls involved a trek to the local call box, which, unfortunately, doubled as a public loo.
So we were not impressed with jolly little Buzby, boinging around on his telephone wire.
"Make someone happy - wring Buzby's neck," was one of the major catchphrases of the late 1970s and early 1980s round my way.
Wimbledon 1979 data available on the blower!
Note: "Post Office Telecommunications". The telecommunications section of the Post Office was renamed British Telecom in 1980 and became a totally separate public corporation on 1 October 1981. See a 1980 British Telecom Buzby newspaper ad here.