Having struggled to get the oil seals in the hubs I'm still left with a 2-3mm gap between the outer face of the oil seal and the front face of the hub. I should have checked on the gap when I took them out but does anyone know if they have to be totally flush with the hub?

I can’t remember off hand, I always push them in by hand, then put a socket on and give a tap to make sure there home, it could vary by make, you don’t know if there made to spec unless it’s LR part,, if it’s sealed I’d be happy with it.

Yep, sealed, square and lubricated. On a Defender hub there's a fairly obvious machined seat and the seal sits below the face, but iirc on an s3 they went flush.

Thanks chaps. Chris, you must have vice like fingers as I had to keep the seals in the freezer and heat up the hub to get anywhere near getting them in. They were OEM too.

I replaced my seals a few months back along with new wheel bearings, ball joints and bushes.
I don't remember any particular difficulty fitting the seals. I just knocked them in with a hide mallet.
Make sure they go in square and tap all round as they go in bit by bit. Finished off by knocking the seal flush with the surrounding casting.