A few years back now in this thread, Doc Rowe mentioned that some film existed of Nic in the Topic recording studio for a BBC documentary "The Other Music" [produced by Philip Donnellan and transmitted in 1981]

Although I have not found a source for that film, a couple of very brief snippets of what appear to be the same footage appear here, at 0:0:11 and 0:1:37...
The Nic Jones story: a voice as unique as his guitar style - apparently a trailer for the c. 2012 "Enigma of Nic Jones" documentary by Michael Proudfoot, this trailer uploaded to YouTube in 2018. (The full documentary is available on DVD from Mollie Music, but unfortunately does not ship to Australia...)