Be aware that the online parts catalog from Rockauto.com shows various front wheel hub seals for the XJ40 and X300 cars that DO NOT FIT!
They have seals such as a SKF 18565 or a Centric 41720003 listed for the application and all of these seals have an OD that is too large to fit into the bore of the hub.
On the XJ40 AND X300 cars the bore on the inside of the front wheel hub is about 2.355 inches and the OD of these seals is over 2.5 inches so there is no way that they will fit, no matter how large the hammer being used to drive the seal into place.

The ONLY seal shown in their catalog that IS CORRECT is the Beck-Arnley 052-3413

 

I recall the same problem from 12-14 years ago. I think application and cataloging errors carry through to many different vendors and manufacturers, likely because they're often working off the same incorrect data base. Speculation on my part, of course. But I've certainly noticed the same repeated errors from different vendors which never seem to get corrected.

Cheers
DD

 

Just went through this same situation with Napa Auto Parts this week. Purchased inner and outer front wheel bearings and seals. Bearings were correct, seals did not fit, their OD being too large.