The boy who has an accident in the assembly hall at the beginning is Todd Carty who would later appear as Tucker Jenkins in Grange Hill (1978), a TV series inspired by the success of Please Sir! (1968).
Class 5C were meant to be 15-16 years old but when this film was made, David Barry (Frankie Abbot) was 28; Peter Cleall (Eric) was 27; Liz Gebhardt (Maureen) was 26; Peter Denyer (Dennis) was 24 and Malcolm McFee (Peter) was 23.
Malcolm McFee wears a wig as Craven, as his real hair was considered too short (he had recently been filming Oh! What A Lovely War (1969)) to suit the character. *Oh What a Lovely War was shot during the Summer of 1968, three years before this film, so that is unlikely to be the reason for the wig.
The copy of the Daily Mirror that Mr Price is reading while walking the street at the start of the film (headline "Philip Drops a Market Clanger") is from Tuesday 22nd June 1971.
Cilla Black's song "La La La Lu (I Love You)", featured on the film's score, was released as the B-side on her 1971 single "Something Tells Me (Something's Gonna Happen Tonight)".