I have posted about this topic before, but I have observed more since then.
Car starts perfectly when cold. Sometimes you have to wiggle the key to start it.
Problem is when the engine is hot, or if the car has been standing in the sun: car will not start. Turn the key to ignition position, everything appears normal. Turn key to start car, all lights on dash "dip/fade" as they normally would, but no click from the solenoid, no sound from starter motor

But! starts fine if you run start or short out the right pins (can't remember what numbers they are) on the diagnostic socket. The only thing I can think of that could be causing the problem is either the immobiliser, or the ignition switch is on the blink.
Any thoughts much appreciated...

There are two types of drivers: Those who dislike BMW drivers, and those who drive BMWs.