Hi Nigel,
I think i found it,had to dig it out of my scrap.
My shaft,cam that is,is 450mm total length.It has 13mm of thread to attach cam pully with a nut.It is 77mm from the right hand edge of the last cam lobe to the end of the shaft where the vac pump goes on,if you understand where i am coming from.Trere is a slot at the back end to drive the vac pump.
If this sounds like yours,post your address and i can organise deivery.
Think i just found a part number stamped between the 6th and 7th lobe,its 894717611.