2001 land rover Disco II td5 not starting - no fault

Check the crank and cam position sensors...sometimes they don't kick the SES light on until they fail. one of the main symptoms of the cam position sensor failing is the "no start, but cranks fine" issue. This happens especially when the engine has been driven and is warm. If the sensor has failed, the engine won't start at all, and everything else will seem fine..the part is usually cheap at the store, and usually easy to replace since it will be near the top of the engine somewhere. I'd start with that and see how it goes...The other sensor I mentioned is also critical in the timing of the engine the "crank sensor" if it fails, it may also cause that situation. The two sensors together tell the CPU where the cam and crank are in their timing sequences. If one isn't working, the CPU won't know where to fire what cylinder, so it just won't fire any of them. ie: No Start. I would replace them both just to be sure. Since you have checked everything else, and it cranks, I can't think of anything else at this point. Good luck. :)

Great things, all these hi-tech bits n pieces...when they work! But that wasn't the root cause of my problem...read on please
I had exactly the same issues with my disco, loads of expensive quotes for repair (and sometimes not even similar diagnoses)....until a wee guy appeared courtesy of the AA call out service. I expected him to turn up , plug in his Testbook and do his stuff, but he was conventionally trained and wanted to do a bit of basic mechanical first-line checks right at the start - and here's what my problem was....
He tried starting it - healthy turnover but no firing up. He scratches his head for a moment and gets suspicious about whether or not there was sufficient compression happening or not (it's a TD5 so it's diesel and needs compression to fire up...that's how a diesel engine works, sure it's got glow plugs to provide that initial fuel ignition, but after that it's the compression which makes it work) Hmm..put the kettle on while I tinker, he says. So he takes the air inlet off and asks me to turn the engine over while he makes his checks. "It's blowing by, very little compression happening in there"
He checks the oil level, says it's high and gives the dipstick a quick sniff. "There's diesel in your oil, smell it?" He asks me when this no-start issue occurs, "it's after the car has been standing for a few weeks while I am away at work"
"That's the problem then, the diesel has thinned your oil and there's no lube on the cylinders so there's no seal happening and therefore reduced compression, so it wont fire up" , he says. He checks out the glow plugs to rule them out and they are all ok.
We just gotta get the thing initially fired up, so he tries a bit of "Easy Start" into the intake (but he does say that if it kicks then due to the high octane content that it might kick back a wee bit)
Fingers crossed on my part and quiet confidence on his part, we go for a start and bingo ! it roars into life.....idle for a few minutes then stops the engine
We drain the oil...it's almost like water the way it runs out and check this out...it's overfull by about 2 litres and it reeks of diesel. So we fill the engine with some cheap oil to the required quantity and fire up again to let it warm up and flush out any residual contamination.
I drive the car to the local auto store, pick up a new pair of filters ( always change the centrifugal filter too , it's a wee bit fiddly to fit it due to its location. I get new good quality oil and set about doing a complete oil and filters change. I put an additive into the oil to help it retain its viscosity in case any piston ring wear had happened.
The following pics are in sequence for doing this, helpful as the centrifugal filter is not the most obvious thing to spot on the engine!

So...where did the contamination come from ?? It turned out to be that I had leaking Injector seals that were passing the diesel back into the oil system - it wasn't an overnight process but eventually it killed my compression if the thinned oil had a chance to drain back down off the cylinder surfaces into the crankcase. New Landrover injector seal kit purchased from Ebay @ around (don't be tempted by aftermarket copper seals, always opt for original LR ones)
That was way over a year ago and despite the car sitting for long periods while at work there hasn't been any problems...but I do check the cold texture, level and smell of my oil regularly.
PS ...the pics are courtesy of another LR owner but are freely available on the net. I do not claim any copyright but greatly appreciated their availablity