Geezer used the John Birch basses until "Never Say Die" album in 1978 on which he used a lot Glenn Hughes' old Rickenbacker 4001FG.They swapped basses, Glenn got a Thunderbird from Geezer if the interview from Bass Player mag is correct. What model etc.? Somebody could invite Glenn to this group...
Anyway, he still used the John Birch bass for the tour (the striped SG -style in a pic JIO posted) until he got this JayDee bass:
I also like that the Sabs were a very colorful bunch of blokes in the seventies. Geezer's fashion sense especially was very eccentric. As is his bass playing.