Thx matey, I hsve actually located a photo I took of the frame number prior to restoring my Sport (PHEW !!) It's on the inside of the drive-side rear dropout triangle -
I have added this pic to my build thread so that I don't lose it !!
Does the numbering format look correct to you? I think it reads
86 033 08 but maybe some digits are rubbed off?
I wish I had taken a better photo now