It's a MK-3 my boy. Stagecoach UK ordered their MK-3s with
AlexanderDennis's 'PS' body simillarly used by our Mk-2s, N113CRBs
and 200 Mercedes 0.405s.
AlexanderDennis was formed in 2001 with merger of Walter Alexander,
Dennis and some other body manafacturers. Due to this, Duple Metal
Sections(Duple Metsec) was closed. 