It might be a joke on "Plunk it" but I think he was portrayed as a clarinet player! (I have tried various searches for clarinet cartoons).

One thing I have noticed is that there are no cartoons coming up with a similar style of figures either. The nearest to the style that I have seen is a series of cartoons called "The little people" (dwellers on a model railway layout, rather like borrowers) that were in the Railway Modeller magazine back in the 1960s 1970s. Now this was the Peco model railway publication and they are based in Seaton Devon so perhaps a West Country connection is coming up again. I should point out that my grandfather lived in Watchet, Somerset.

Robin