So I found a pair on ebay from a seller but each had a different part number. I asked the seller about this and about postage to be combined (each was a seperate listing)
In the mean time I'd tried Euro car parts - not in stock but next day - they wanted £18 + vat, Next tried GSF - £15 + vat, better and they had them in stock. Went down and picked them up - best bit I asked for my discount and lo, off it comes! £13 + the vodka+tonic. Pretty chuffed at that!
Fitting yesterday evening: Was this exciting job going to be a time consuming pain in the ass?

RH link out - 20 mins

old and new - seem to match!

fitting the new RH

DONE! - another 25 mins or so
One side done in less than an hour!
I had planned to just do one side given the time and usual problems encountered- but the RH one was so quick to do that I thought I'd crock on with the LH

Even quicker - the whole task in around 35 mins..
Even had time to go for a quick spin to try them out - sweet as a nut.
Even had time to adjust the auto choke that was stopping the second carb choke from opening - done and dusted.