Electricty Board Smash Hit Sale advert

[Lord Thames]

15'24" into this - the music from the Electricy Board's 1984 'Smash Hit Sale' adverts, which I loved at the time, and still do now.

The ad may date from 1984, but the music is clearly from much earlier - this track is one of my holy grails, can anyone solve a 34 year old mystery?