So I've replaced the battery for a new'un, and that helped..for a while, but I'm basically back to cranking the hell out of it.
Now the glow plugs don't illuminate in this warm weather, and that's helped me figure out what the problem could be.
In the morning I turn the ignition on and don't crank. Then, off, then on, then off...etc. Appx 4 -5 times, then the car starts OK.
I'm thinking that the diesel is running back down the pipe to the tank...or thereabouts.
So I've ordered a 10mm non-return valve from ebay. Not sure whether to put it near the filter housing or further down the line, so any advice is welcome.
I've also ordered some 3.2mm braided to do the leak offs. I've heard lots of people say this could be the problem but in honesty, I've noticed (from googling) that it very rarely fixes the issue.