Crunching thud from left wheel

I knew my luck wouldn't stick, went to the Lake district at chistmas and got stuck up a mountain in serious snow. I kind of pushed the old girl a bit hard trying to get up the last bloody 20 metres but she lost her footin and started slippin back - resulting in us having a 2 hr detour - we weren't happy to say the least. The fun really started when i went to turn at a roundabout and the loudest and severe thud came from the left wheel. The front of the disco raised up and then crashed down again. It only happens on almost full steering lock, fine going straight although the steering wheel doesn't look straight when goin straight. I've had advice that it may be the CV joint, it feels like somethings bent and hitting the wheel when I turn - sounds expensive what ever it is. I think when i was trying to steer one direction and the front of the disco was going another and sliding backwards in the snow, something must have been pushed that bit too far.
Anyone got any suggestions - go easy please???
Ohh it's a 92 200 series tdi diesel discovery.