Hope this may help others with starting problems.
For some reason my Discovery has always been sluggish to start in cold weather. If left for 4 or 5 days it wouldn't start. I've tried fitting a new earth lead straight to the engine and replacing the battery which only improved things the first year. When jump started from a charged battery it was fine.
It was a bit like the battery had a slow drain on it when parked, but putting an ammeter between the lead and the terminal only showed a 0.02amp drain which I guess was the clock and little else.
Having a few half good batteries kicking about I decided to fit it with twin batteries. If you remove the jack and the wheel chock and throw them in with the back with the rest of the detritus, and displace some rubber mounted gismo on the inside of the wing (think it's something to do with the EGR which I don't use anyway), there's just enough room to slot in a second battery to the right of the radiator. A couple of heavy cables run across the front of the radiator, rather neatly held in place with printed clips finished the job.
Although we haven't had any really cold weather yet, it's made a massive difference to the way it starts ... well pleased.