Just wondering if you have tried the Bates Wide model? I have one for my draft x–the gullet plates go to 4XW.
Also, just as an aside, you mentioned ordering from Ebay UK. I’ve bought a used saddle this way. It’s very easy, just make sure you buy from an experienced seller and use PayPal and the chances of fraud are extremely low. (And the exchange rate is good right now).
Good luck!