Ok, I've changed the chain and the rear cassette (had to downgrade slightly from XT to SLX but hey-ho!)
So everything is fine with the front chainrings and we have sweet shifts up and down in all combinations
and meshes good even under load ie no skipping nonsense.
However, before I swapped cassetes I noticed slightly differing letters on the spider, (RG and JH) is this just because I've
got the SLX version or something else?