Good luck with that, SeanC.
I'm a bit surprised that this is a not uncommon problem. ( Well, maybe its just you, me and CarloL in the whole world).
I regret trading in my 2011 3ltr diesel X5 😞 Thought I was saving money on the road tax, but a new transfer box and a rear axel rebuild put that one to bed..
Il ook forward to hearing how you get on.
Regards,
Rod