Had a go at the wipers this afternoon. On dismantling the dashboard and getting a meter on the wires I discovered electricity was getting as far as the motor. Something in the region of 8 volts. Switching the stalk to high gave me about twelve and a half volts. So that's how they do it. The motor itself wasn't doing much, apart from the fact that it was getting hot. Then I smelled the smell again. Who would have guessed? Overheated windscreen wiper motors smell like burning soap powder. I got a spare motor out of the shed (I'm accumulating a lot of bits of Land Rover round the back of the house) and tried that. It's little bendy wire 'rack' went in and out appropriately at the relevant stalk positions so I fitted it. Then when everything was back together it all jammed with the wipers in mid stroke. The driver's side wheelbox was a bit slack, so with the resistance provided by the wiper, the rack attempted to jump a tooth on the cog, thus jamming it. That might be what burnt out the other motor. I took the dashboard completely to bits and got the wheelbox out and banged it with a hammer until the rack was a bit more snug. Oops, too far, it wouldn't move at all. Gently opened it up a fraction and it was just right. All back together and wipers working. Went for a drive and happily washed and wiped the windscreen at every set of traffic lights. Some of the dead flies are starting to come off now.
That motor was new in April 2014, so I'm not best pleased with it. In fact the windscreen wipers are turning out to be the least reliable part of the Land Rover. Even more faulty than ECUs.