I had the same issue with mine, but its not hard to have another one made up, measure the distance between the centre of both UJ's (transfercase to diff) with the jeep stationary and all wheels on the ground. They do say to jack the jeep up and measure again for suspension extension or droop and then measure under compression (suspension compressed) but being a 6 they hardly change at all. Once you have the measurement take your original driveshaft to a speciallist (there must be heaps in the UK) and they will remove the UJ parts and weld in a new longer tube. I had them make the measurement I took happen when the slip yoke splines were half way in their travel, that means I have about 4'' either way of travel.
