I fitted the two 0.25mm shims (I had them laser cut) on either side of the pressure ring and OMFG!
I probably should have only used one shim, as the it's like I have a welded diff! :-/
With one rear wheel off the ground, I can not for the life of me turn the other wheel! I can get up my driveway piece of cake now!
Making 90 degree or U turns makes the inside wheel skip like a bugger!
Will see if it loosens up over the next few hundred KM's but I think I may have to strip it again to remove a shim!
Thanks for the help, fellas!