New sprocket fitted!
Used new nut and washer.
The new nut was iffy and didn't screw on nice and smooth as expected. I had to screw on and off a few times, cleaning with WD-40 in-between each go. The thread was a little dirty but mostly it seemed to be machining left overs I removed. It wasn't perfect but screwed on a little easier afterwards.
I discovered that during the many attempts to get the nut off, my socket had actually cracked....in three places!! Just goes to show how much pressure we were putting through it!
Thankfully Halfords are open until 8 and 5min drive away.
It gave me the chance to buy a decent socket and I can recommend to anyone else attempting this to get a Halfords Advance 27mm Deep Hexagon IMPACT socket!
The 5 sides means that the socket holds the nut better and the deep socket gave enough room to apply pressure on the torx drive and stay clear of the engine casing and frame!
Let the new chain soak in chain lube before fitting.
Fitted the new chain using new chain tool and I can say that it does make a difference, although fiddly.
I'm disappointed with the quality of the nut, new and old.
It's incredibly soft alloy and I can't stress enough how important it is to use a good quality, tight fitting socket. Even when tightening up I had to be careful not to let the socket slip. I advise building up the strength using a torx wrench slowly and make sure you take in all the slack before tightening.
Don't forget to tighten the back wheel and adjust chain correctly before finishing up.
Overall this experience has provided me with valuable experience and I'm glad I did it.
However, it was unnecessarily difficult and hard work, it's sadly lowered my opinion of Kawasaki significantly.
But I'm grateful for all the help and advice from everyone and I can say that it would have been a lot harder and more frustrating without you all, the forum is superb!
Thanks to everyone