Hi Dave,
I have slight concerns about that sellers product. From the photo on the listing it appears that the center housing is a used one that has been shot blasted. It appears to have cleaned up rust pits. While this is not an issue on the body, they do seem to extend to the mounting flange area. It's not a problem per se, but if they have not masked the casting properly there could be damage elsewhere. Personally I'd rather buy a all new parts CHRA or just a refurb kit (<£40) and do it myself. As mentioned before, the issue with the refurb kits is maintaining the balance of the rotor when you put it back together.
Robert G8RPI.