One thing I like about this episode is the dramatic 'edge' it has.
The episode does rely a lot on the book, and fortunately some of the words are able to be put into the characters 'thoughts', where the actor reads what he is supposed to be thinking. I like this device, it's very effective and was also used in Cheering Up Gordon (or was Boarding House Caper?) and There Goes the Groom.
In 1974, the series relied a lot on strong dialogue, so this may explain why the episode is quite a gritty one, as it uses much of the text of the book 9 years before.
Roy Clarke's later LOTSW novels were much tamer.
My only regret is that more of the first book couldn't have made it to the screen.
One has to wonder how it would have turned out if made in the mid 70s with Blamire in it. The book captures Blamire very well, though of course we are so used to Foggy being in this story.
It's also worth noting Nora and Wally Batty have very minor roles in this, in fact I don't even think they feature in the novel, though Wally Batty is mentioned.