Well I admit that I need to eat my words re: Win10

... it's not as bad as I'd thought, now I've managed to eliminate much of the twinkly stuff I find that I can actually use it - so much so that I'm embarking on an upgrade program to my new workstation.
It came to me as an HP Z800 with a single quad core Xeon 5550 cpu 12 Gb Ram, a Samsung 120Gb SSD, a 1Tb HDD and a Nvidia FX580 graphics card.
I knew that the graphics card would be marginal for my applications (Fusion 360 and Scanect) but the system was a solid core for upgrading.
Yesterday I picked up a GeForce GTX 660 s/h on eBay - it happens to be the over clocked version but the base model would have been fine - (this is a work station not a gaming machine !).
I also picked up a pair of the heatsink / fan assemblies (£21) (allowing me to install the second processor) and a matched pair of Xeon 5550 cpus for the princely sum of £16
While at it I also got a further 6 of the 4Gb Registered DDR3 DIMM's a the bargain basement price of £38.25 - I'm not sure I'll be able to install all 6. They are identical to the 3 already installed but not sure if each CPU has to have the same number of DIMMs, also I may run into power supply limitations - this machine is fitted with the 850 watt PSU - there is an 1100 watt version but they don't pop up on eBay very often and when they do they are not cheap.
I must say working inside this machine is a joy - so easy to get at things.