This is one of those pages that helps to date this comic. The inclusion of the theme song from the ecologically sound children's TV series The Wombles is one clue but not conclusive. (The Wombles seemed to be on TV for years!) The reference to Colditz, however, is far more revealing!
According to Television Heaven the TV series Colditz was screened in the UK between 1972 and 1974 which, as I'd kind of worked out, would have made me about fifteen or sixteen.
For those too young to remember (and for US readers of any age since I understand the series was never shown on your side of the Pond) Flt Lt Carter was played by David McCallum. Not that you'd recognise him from this page (although I think I got the moustache about right!)
On a purely personal note, I do like the white rabbit's line "Who are you calling an hallucination?" I don't know why. Just thought I'd mention it.