Disco transfer box problem?

Hi everyone posting this on behalf of a friend, he's got a L reg disco 300tdi manual, basically he went to cowm quarry pay and play end of last month, had a great day out but the landy developed a clicking noise from the front drivers side wheel he carried on for an hour or so but started going paranoid and didn't want to do anymore damage and due to him having to drive home ( around 30 miles away) he parked up and left it until it was home time, now on the way home he got about 3 miles from the quarry and there was a loud bang and there was no drive for a few seconds then the drive came back then there was no drive and was very jerky then again drive came back but was still jerky and it carried on like this so he stopped and got recovered home, now basically I just want to no what the actual problem is, a few of his mates have said its the transfer box but I was thinking more half shaft damage or a diff going due to the clicking noise and the intermittent drive, any of you guys had this problem or any experience with similar symptoms?

Front cv has gone I would have thought. Clicking would be from the bearings in the case being loose.

If it isn't this then half shaft but normally half shafts go when you are actually putting the transmission under a lot of stress. CVs go through wear.

from what I read on shattered CV joints on our forum,
it would seem that for a lack of a grease gun full of molygrease being pumped into the swivle hubs reguarly, we read of dangerous outcomes from joints shattering.

get that grease gun or ep 90/140 out to bits ya cant see..

Some new info, just spoke to my mate who's land rover it is, he said also when he was trying to get up hills only the front wheels were turning and the backs weren't so it was sort of in 2 wheel drive, would this be the transfer box?