Stick it up on axle stands and let it run, check for drips with a high powered torch...
If the diff is made in 2014 then is should be the newer type where the oil seal is a part of the shaft, (if you had the serial number gripper should be able to confirm this), so there should be no way the oil can leak down the splines. Behind the seal there will be oil splashing about all over the place, but there is no direct feed down the splines or anything like that.
Is the collar nice and smooth? No damage at all that could effect the oil seal?
The rubber o ring doesn't form any part of the oil seal, it is more of a dust cover. You can run without it no problem if need be.
I would give the seal and surrounding area a good clean so there is no signs of oil at all, then take it for another drive and inspect it after.
I would take the shaft off, fully degrease the whole area and surrounding components and the splines on the box and inside the shaft.
Put some thick cv grease (only a smear) inside the shaft and put it back on.
If the gripper is like the Quaife then the S/N should be on the wetside, remove NS drive shaft and should be stamped there, maybe James or anyone else confirm.
As sudgested, totally clean up the area with spray brake cleaner to get all oil out.
All it takes is a few drips to make it look more so will have to run it for a while, otherwise you would have had a pool of it. Interesting about the collar on the gripper though, wonder what the quaiffe one looks like?
Probably been leaking the whole time the box has had the gripper.
Needs cleaning up, and then inspecting IMO, I'd poss consider silicone on the splines, at the end of the collar, so it 100% can't be that, and then look where to go from there.
As a further thought, its not coming from speedo drive or something? I can't remember if that box is speedo drive or not, I know your car isn't obviously.
its not oil feed, the gearbox has no oil pump so no way to move oil about like that, the hole is left over from Mk1 Clios that had a pin to hold that shaft onto the box.
You're going to love it as the CV grease slowly escapes all over the bay.
The splines are dry no wet feed (as Alex said no pump). The speedo drive is a black plastic sensor at the rear back of the box it sticks up so the loom plug connects to it.
I'm jealous. You going TRAX?
I'll teach you how to string a car mate
Just get to know the local tracking guys!
Mine costs a mars bar and a lucozade haha
Good day yesterday Martin, shame about the problem hopefully will get to the bottom of it soon, if you ever need a hand give me a shout
Massive love for this
Seriously love this thing mart
I hate it.
Excellent mate. Hopefully that's the oil leak and the knocking sorted then. Still a bit surprised they were still using the glued collar with a 2014 diff though.