Thanks CooperMan, I thought that might be the case. Worth noting that my replacement from mevspares has usable innards in a pinch. Actually, if I'd had a fitting for the spur, the part would have fitted fine. It cost £34.50 including postage.

Hi Treesurveyor,
I hope this finds you well. I steadfastly remain fond of you and your car. It has me braving the problems of posting here.
Firstly, generally speaking, the current loss of even minor skills cost owners and their Morgans a lot.
But I know you, personally, to be a braver sort, merely in the need of a bit of guidance and I am letting that guide me. If this post is deleted, so be it.
Up until the new era, this was a quick repair that owners would do themselves. The repair kits cost 10 quid and that fixes them buy replacing all seals and such. Figure 15 minutes inexpert labor merely using the needy MC as your guide.
Those who wanted a more permanent solution usually, (if they are not into exotics) have their hydraulics stainless sleeved..which costs the same as a new master/or slave cylinder at normal retail prices.
https://www.gomog.com/allmorgan/Plus8Clutch.htmlIf you can sharpen or change a chainsaw chain, you are far past the skill level needed for something like this. Tying shoe laces is harder.
Lorne