Thanks Guys, Ideally I'm looking for a cheap 2nd hand one sitting on someones shelf to try out. I am not sure what rate suits me.
At the moment the bike has a 4.1 in it which is too soft. When I go on the Racetech website and use their spring rate calculator for this model it tells me at 88Kg, I need a 7.2. That seems very high to me so I am willing to try something between 5.5 - 6.5 as a starting point to see how it feels. It may well work out that the bike will still feel too soft and I do need 7.2 but a spring at a rate between 5.5 - 6.5 will at least be a vast improvement over what I have now.