The prison doctor reluctantly confirms Fletcher had previously had surgery on his left knee, however he fails to notice that Fletcher is erroneously now complaining about his right knee.
Earlier in the series, Bunny Warren cannot read. However, he is seen reading from his hymn sheet in the choir.
Mackay mentions that he went to the Governor's sherry party. However, it is revealed in the following year's Christmas special that the Governor is teetotal.
At the start of the special Godber asks what Christmas is like at Slade, to which Fletch relays a tale about turkey with 28 legs and no breast, pertaining to Fletch already being behind bars at Christmas and it being Lenny's first. It had been established in the first episode that Lenny and Fletch arrived at the same time on the 1st of Jan, so therefore he could have had no knowledge of what Christmas was like at Slade prison; also Godber already knew this and therefore renders the question moot.