Fitted mine eventually yesterday, but I can't get the two nylon washers to fit, has anyone else had problems or got a suggested solution!!

More worryingly, once I had tightened the connecting nut and bolt up, I couldn't move the lever. As I loosen the nut and bolt the lever becomes progressively easier to move. The bolt is currently a good three quarter turn from tight, yet the lever is still nowhere near usable on a day to day basis.

I have fitted everything as spec except for one nylon washer as mentioned.

Anyone able to suggest a solution?

There are 2 different types of holders for the Nylon washers. As there are also 2 different types of Linkage.
Make sure you have the correct Nylon washers for the correct linkage.
If you are still unsure i can order you the correct ones! Just need chassis no :)