According to this source
the cello players were Francisco Gabarró (=Spanish. He also performed the cello part on 'Yesterday' string quartet), Dennis Vigay, Alan Dalziel and Alex Nifosi.
So, if Francisco Gabarró is named in the first place, this means that he was the principal of the cello section, hence, situated at the very right corner of the conductor..., right??
Cello player #1:
Cello player #2, you can see his face and his left hand behind that violinist (=he shares the music stand with cello player #1):
Cello player #3, you can see his face behind that violinist and in the front middle of those two Double Bass players:
Cello player #4 (=he shares the music stand with cello player #3):
So, my hypothesis read:
From right to left of the photo, the cello players are Francisco Gabarró, Dennis Vigay, Alan Dalziel and Alex Nifosi...