Probably about 48p, IIRC.
... we used to have a pub near our school that'd let 6th formers in at lunchtimes if we took off our school ties
... he just 'assumed' everyone was 18 (hic)
We had halves though, and played pool and space invaders.
Just occasionally we'd forget about school for the afternoon, nip into the offy and go up the local footy stadium, sit in the stands and continue... these days, I'd assume kids drinking like that in the afternoon were ne'erdowells, but we were really quite nice, and never caused any trouble (apart from that time we tied a friend up with sellotape and left him there)