Double crikey, here's a film actually made by Scritti Politti for the BBC program Grapevine, explaining how to make your own record. Featuring members of The Door and the Window, Desperate Bicycles, and lesser known DIY outfits of the era, as well as Sue Scott from Rough Trade, record engineer and mastering maestro George Peckham of "Porky Prime Cuts" renown. And various Scrits, including a rare sighting of fourth member / organiser Matthew Kay.
Seemingly the "promo" for "P.A.s" in the previous post was made from out-takes from this production. So filmed in 1979, but apparently broadcast in 1980.
There's tantalising references to the guide-to-DIY booklet How To Make A Record that Scritti published and circulated, which the Grapevine presenter invites viewers to write in for. Has anyone got a copy of that?
Stop press 27/06/19:
Found pages from How To Make A Record at this tumblr stillunusual. It even had a catalogue number - SCRIT 3.