Slight setback getting the frame stripped and photographed, turns out the bottom bracket's plastic cup has perished its one of those *** sealed units with plastic cups both ends. The drive side is now pretty stuck, looks like I need to drill it out or blow torch it - so I'm holding off putting anything flammable on there like paint stripper lol

Interestingly there are some forum posts out there with raleighs from the mid to late 80's that have the same type of bottom bracket things like the Raleigh Road Ace, which look like a pretty similar build to this bike. The bottom bracket could have been replaced of course and there are no rivet holes for a raleigh head badge, so the mystery continues.