Hi,
I would change the axle case.
If the axle is actually damaged then you could try places like equicar ? and the salvage merchants in the monthly Landy mags.
I've even seen axles for sale on Ebay at good prices.
Depends what work you would take on
Try a Landy garage thats not a dealer they'll probably sort things out a lot cheaper than 6K
Good luck
Jim