I have here a steering wheel centre with the usual big "M" and a horn push assembly. It looks spot on but the problem is that its just a fraction (I mean 1mm or so) smaller than the hole in my mountney steering wheel boss (aka hub etc). Its not thicker minor centre (which i think is much smaller). Now I always thought the mountney boss was the right size for the morris centre (I know that the Les Leston wheel I had on the car when I bought it had the right size hole in the boss).

So whats the problem here - is my boss the wrong size or could this horn push be the wrong one, just "almost" identical to the mini one?