Apart from the gear shift lever there are two levers. Am I correct in assuming that the front one controls 2 to 4 wheel drive and the rear one controls high to low range ? There also appears to be a warning light which suggests the vehicle has a diff lock is this correct ? Thank You

yess you prety much have it right... the diff lock is done independantly from each wheel by a special tool...

havent done it yet , but will soon, take mine out to the diunes