Phone Revs Racing 0121 501 3321 and Ask for John or Nick! They do a few types. I got wilburs progressive springs for my 796. Couldn't find them anywhere but they sorted it in no time. Revs Suspension Services
I'm surprised they supplied you with those, isaac, as John and Nick have always advised me not to use progressive springs as fork oil is progressive by nature when compressed.
Oh I could be wrong I haven't got a clue about suspension (hope it's progressive I fitted it according to the instructions for progressive), this is the actual spring. does away with the spacer in the tube cost about £60