These are all 1950s UK school posters - two by the renowned artist Ella Ruth Boyce - mainly approx 50cm x 40cm or, as the posters themselves would probably prefer it, 19in x 16in.
They are Doctor's Day (those tonsils are porbably coming out), Post Office (people writing cheques!), Joe Black's Fruit and Vegetables (lemons 2d each, no avocados) and Play in the Hall (absolutely no Health and Safety).
The 'Play in the Hall' poster has a little water damage to the bottom right hand corner (see photos) but otherwise the posters are in good condition considering their age.
A rare collection by all accounts.