Hello Michael,
My reference to wheels was the centre part of the wheel which is black plastic with a metal tyre fitted to the outside, wasn't sure if it had a name or term in it's own right, the wheel sets I was referring to as a pair of wheels and an axle.
With my early attempts at improving running I tried to adjust the pick-ups which made matters worse, By the way my class 14 is also fitted with Loksound V4.
Stick with it Michael I think you'll get there, I almost gave up with mine and left it at the back of the loco shed for a few months, glad I didn't give up.
Allan