S21·E69 Episode 1690 (Thu 27th Aug 1992)

Herons have eaten through a fence at the fish farm and are stealing the fish. Alan refuses to spend money on new netting and asks Seth to mend it. Rachel persuades Mark to open his exam results. He is surprised to find that he has passed the two subjects that he sat - he got a C for Art and a D for Geography. Rachel thinks that he should resit his English or enrol for art college. Mark is determined that he is not going to plan anything. Alan climbs a stepladder to try and fix the netting, but Seth makes it wobble and he won't help him anymore.