Re: No brainer shirley?
IIRC any large catering situation in the 1950/60s used to have a large urn of tea with the milk added. In those days tea was always strong with milk and lots of sugar. Usually Typhoo, P.G. Tips, or Brooke-Bond. As a bonus there were often collectable sets of picture cards on educational subjects like wild flowers or stars.
Memories of after-school hobby clubs - and our school canteen serving a cup of tea for 1d - and a slice of custard jam tart for another 1d.