OK after much deliberation I decided to go with the Dobinson suspension kit. Very happy with the outcome and the lift from centre of front hub and rear axle are as follows. Front 550mm and rear 640mm and that is with all the bar work etc. I have fitted 3 degree wedges, spaced the gearbox crossmember mount up 6mm, rotated the centre bearing but have made a 1.75mm shim for this.
Shudder not really noticeable but the tailshaft spacer will see to this. The centre bearing is under a massive amount of stress at rest and the spacer should help alieviate this. This is also unweighted and the test will be when I hook up one and a half ton of boat and trailer..................