Regardless of being fleeced at sale the onus is still with the garage to replace faulty items on the car. The amount of time it took Landrover to fit you in wasn't great to be fair as the more time that passes the lower your rights are for refund or repair. When I bought mine, no more than 2 weeks later the ABS pump went and had to be replaced, the garage took it straight back, gave me a courtesy car for 2 weeks and replaced it, costing them about £900. No fuss though and all sorted for me. Good luck with it. Don't take any of their crap though you want full replacement parts (at a garage of their choice if necessary, or a reliable one of yours) with full receipts for the work carried out. That or you don't want the car. Once they realise that that's the hand your playing they'll probably stump up for the repairs as opposed to losing £16k. It's a much better outcome for them. Always kick up a fuss, always complain. You never get anywhere without it.

Also I find it particularly useful to walk into the showroom/onto the forecourt, collar the nearest bod and start going off at them loudly about how you've been sold an un-roadworthy car etc etc, it's gotten me plenty in the past. They don't want other potential customers lost and that's the upshot.