can you link to the cover. i'm intrigued that anyone managed to keep four dvds worth of these shows based on three things. One, the series ended in 1984 which isn't yet the height of the video boom in Britain therefore reducing the possibilities. Two, the cost of vhs tapes at the time was certainly prohibitive to keeping non-essential recordings and three, the fragile nature of the medium. I lost loads of tapes to jams/shredding/twisting/tearing etc.
I saw something where it said it regularly had ten million viewers but that needs context - we only had three tv channels at that time and it probably gained a lot of viewers being sandwiched between the football results and either the generation game or little and large (neither of which will mean anything to you I understand that). The one you mention seems to be the last (except for two specials) of the original series three year run. i know that wasn't an episode I had because i know where i was in october 1984.
https://en.wikipedia.org/wiki/Pop_Quiz#frb-inlinemost of my 600 or so vhs tapes look something like this one that i just transferred to three dvds to get ultra high setting
howard jones manchester apollo 15 march 1985 rebroadcast from 7 june 1985 with extras HQ
omd Sheffield city hall 14 june 1985 HQ
andy summers/robert fripp rehearsal 1985 plus interviews
go west goodbye girl on top of the pops
china crisis you did cut me/king in a catholic style live on bliss 23 august 1985
spandau ballet live london scala july 1980 black and white
sting moon over bourbon street acoustic from 'walking to new orleans' documentary
sting love is the seventh wave live montreux 1985
suzanne vega Luka 'wogan' tv show 27 may 1987