Its been a loooooooooooong week and this is a stupid question…. but I have just put a QR clamp on the seatpost, does it really matter which way it goes ?

Meaning the bolt on the outside or on the inside…

some have a small lip around the top – what make/model?

Yes.

Some reckon the split should align with the slot in the frame, some others (including at least one seatpost manufacturer) reckon it should be the other way around.

I have a identiti QR.

I was thinking….line up the split on the clamp with the split in the seatpost….

i don't think it matters….. however, i run mine with the slots opposite to one another (both frames forward facing seat slot).

I was just checking as I didn't want to get pulled up by the MTB police in the group… lol

I tried mine back to front once (i.e. split opposite the slot) just to see what happened. The post just plopped down into the frame.

My understanding is that it's better to have the slot on the clamp opposite the slot on the tube to help prevent ingress of debris