There is a lot of choice with handling as so many manufacturers and after market suppliers have solutions. For the front suspension there is fac damper rods with progressive springs. There are possible other later forks with the same diameter. In the end I have gone for standard dampers from stein dinse. They were ordered and delivered within a few days.
Here are the forks apart. I used a 11m spanner and circlip pliers to put them back together again. The dampers are bolted on to the tube and the spring covers the tubes. The bottom alloy fixing locks in place and is held all together by the bottom allen screw. I added 50cc of oil to the forks. This is just to lubricate the forks as the damper rods have oil internally.