OK lads and lassies no need to reply,

I found out what I was looking at was the nipple for the vacuum hose.
I fitted the Scottoiler today without any issues.
Didn't even need to take a single panel, nut or bolt off the bike

. Just one tight, fiddly nipple bung which was way up inside under the tank

. (no easy feat with giant sausage fingers)
definitely need to get a workshop manual!
Cheers all
Bigred