I'm not 100% on what hubs he's using to be honest, i think they're off another vauxhall of some sort.
It's not in my best interest to pay attention to things like that so i keep the fire full of coal and make a cup of tea until the topic of conversation changes
They will HAVE to be off an XE vauxhall or they wouldnt fit the shafts.
There are two options to fit:
the bodge way is to machine the hub to take nova bearings, they then break
the correct way is to machine the hub carrier to accept audi bearings, and then only slightly machine the hub to fit that
Most people do the first way cause its cheap, but its also rubbish!
Ive tried both, and broke plenty of hubs done the first way, so will now only do audi bearing route!
Ask him which he has done, if its the first one, I can link you to an article I wrote for total vauxhall magazine about doing it properly (there is an online version on a forum too)