I rebuilt mine about 8 years ago with a seal kit, it took me a day and was a bit of a faff but it hasn't leaked since so was worth doing.
I didn't have access to Rave manual then and my Haynes manual just said it can only be done by a dealer so I looked in an old Haynes manual for the Range Rover classic and it told me everything I needed to know!
It's definitely worth a go if you feel inclined.
Cheers, Peter.
P.S. If anyone wants the info on this, PM me your email address and I'll send it to you