Factual error: Throughout the whole show Godber, 'Bunny' Warren, McLaren, the Prison Governor and many of the guards refer to Fletcher as a Cockney. He even identifies himself as a Cockney on a number of occasions. However, in several episodes he refers to his upbringing in Muswell Hill and in this episode he refers to his having been born there - and we see his old stamping ground in that episode when he gets a weekend's compassionate leave. Nobody from Muswell Hill would ever refer to himself as a Cockney - Muswell Hill isn't even in East London!
Continuity mistake: At the end when Fletcher returns to his cell after a weekend at home his cell is on the ground floor. All other episodes it's the first floor.