If it was me, I’d ‘replace’ - not repair or treat.
Surprised an excellent 4x4 place does not offer this?
I did mine myself, but most places ought to be able to quote you to replace them. New ones are readily available (your call, but personally I would use new rather than a second hand one).
If you struggle, call Freelander Specialists. They will be able to do these for you while you wait (they’ll loan you a hippo to go and get a brekkie

). 100% excellent service and all parts ready and available, but you’ll pay £. I’ve used them once for my F1 and once for my F2 on bigger jobs that I wanted doing.
www.freelanderspecialist.com