Low range problem??

Hi everyone, have not long got my first range rover based vehicle so am quite new to all of this. One main problem I have is that the low range doesn't engage properly. I put it in low and lift the clutch and it will pop back to neutral. It will stay in if I hold the handle while i release the clutch but if I change gear, same problem. What would be the most likely cause? When I put it in high, the lever clicks into position convincingly but not in low.
Its a 78 3.5 V8 classic based car. Any help or guidance in the right direction would be greatly appreciated.

Craig

The probability is that in it's previous life the low range was never used. You need to get under the car and give the mechanism a good soak with wd40 then back in the car give the lever a good working back and forward. It may help if you pull the rubber gaitor back from the inside to give it a bit more freedom until it has eased off.