bit of a numpty question I know, but which way round should the split in the race face when placing on fork crown – at the front or the back? does it matter?

Don't think it matter, but I suppose if you are concerned about such things, it might get less mud in it if the split is tucked away at the back under the frame

…it might get less mud in it if the split is tucked away at the back under the frame

I was going to say the opposite! I gather more crud from front tyre spray on the rear of my lower cup than on the front.

Would it not stay drier if next to the crown?

There's you answer
Put it at 3 or 9 o'clock

I like mine to the left.

There's you answer. Put it at 3 or 9 o'clock.

What about extreme side-winds?

Thanks for the replies everyone- I'll think I'll try to one or other side, perhaps to the right as thats the side I always seem to fall off the bike

Put it the other way for sure, it'll counter-balance your tendency to fall to the right 😆