what have you actually tried to do ?
i'm assuming you've read those links posted before ? - seeing as it's just levers and cogs there's nothing at all complex about it, and it's often just from lack of use that things get stuck - getting the GB nice and warm by going for a long ish drive then blating everything with a release agent normally does the trick
if you take it to a dealer, and you manage to find anyone there who isnt a teenager, they are more likely to say you need a new GB or other expensive part
you'd be better off looking out for a small ocla indi LR garage - who is likely able to resolve your problem within a hour - or at least give you an honest quote for the repairs
even better find a local landy man who will fix it for some beer tokens
how far are you from basingstoke, am sure daft wouldnt mind a visit from a blue eyed blonde