So, I bit the bullet and bought a new clutch from
Superformance.
Despite being closed for stoke taking they shipped me out a new plate
and drop gear nut.
I found a great website that details the clutch changing process. http://www.camerafilters.com/ec/clutch.htm
The guide is possibly a little simplistic, and understates just how much work is involved, but it covers all the angles!
I had one other unexpected surprise; the high pressure oil pipe between the cooler and the block suddenly fractured, so this too needed replacing.
The 2nd image shows the flywheel with the bell housing and clutch off.
The 3rd shows the transfer gearbox
The 4th, this is the enormous pressure plate! it is twice the size of my old Spitfire clutch.
The last picture is the whole thing reassembled. It took about 5 hours to do, this is not counting the number of times I had to take the bell housing off due to silly little things going wrong. I even had to make an unplanned call on Maranello to buy a new split ring for the input shaft.