[Bigsmith] That's the fella.

Pen got it with "Some Mothers Do Ave 'Em". The 'Morse' reference? Apparently the composer (Ronnie Hazelhurst?) got the rhythm (with slight licence) from spelling out the programme name in Morse code. And thus we have the short them I quoted in its entirety. May well be the cheapest ever original TV theme tune, with only 2 flutes playing it.

I did wonder about Some Mothers, as indeed Dangermouse but stupidly didn't think to track down and listen to them to check. So I lose two points...

Bigsmith has it! Dangermouse it was!