Roy, If you have no suitable socket to remove the points retaining bolt, does this mean the points have never been off to be cleaned and checked under your ownership? I hope you have not invested in electronic ignition when all you needed to do was give the magneto a bit of TLC. Or is there a further underlying fault?
I use a good old authentic Lucas Girder Wrench and a light touch.
Nice Jaguar, class axe.
Swarfy.