The usual explanation is excess play in the propshaft, although that's also pretty noisy. The manual gearbox can also be pretty reluctant (mine hates 2nd gear for some reason) but LR have yet to recognise that - or anything else much - as an 'official' fault. But as yer man says, stand your ground with the dealer: if something's changed, you know it has and you know that it shouldn't have done so. The dealer doesn't.