Another vote for Corteco seals.

Breather pipe is brand new. My last one did have damage so I put the leak down to that hence why I changed the breather and the seal

The flange was nice and tight going into the seal so I don't think it's that and I can't see the pressure being high enough to blow it after 1 drive. I'll check the banjo bolt to rule that out

The one I got looked pretty good quality, thankfully not britpart or the like. If it started leaking from the old one and now this new one then I'm inclined to believe there's something else going on but I'll double check the banjo bolt. I use a...

Nope but it's not the original bolt that's in, it's a newer one I fitted. I'll take it out and check it though. My hub seals are still good, it's just the pinion seal

Didn't see any grooves and marks worn into the flange, it's still in pretty good condition and isn't that old

Anyone got any other ideas. My rear diff had started leaking (which I've never had an issue with). I thought that the cover plate gasket and pinion oil seal had blown due to a damaged breather pipe. Replaced both today and also replaced the whole...