Cam belt slip
Your story is almost identical to mine!
I left to go on a long journey, but heard loud rattling noise then stalled at junction. As with yours, mine wouldn't start again, but sounds OK on turn over (without firing). I didn't smell any burnt plastic though!!
The AA man went through some simple diagnostics and said that the fuel rail pressure is good and crank sensor is operating. He towed me home (1 mile!) and I plugged in my laptop ECUscan and there was a crank sensor error P0340 recorded when the engine was running (RPM at the time was recorded as 1600).
Took the cam belt cover off and the belt looked good, but the belt was loose! This is obviously a major issue and would suggest the belt has slipped. If I'm very lucky no damage has been done and I can readjust the positions and tensioner, but need to look up how to ensure positions.
I'll need to get the right engine mount off to get a proper look - but I'll let you know how I get on!
My locks, ABS and DSC started to play up a bit, but I think this is linked to low voltage from my battery as I turned it over a lot this morning!!
Battery is on charge and I'm going to buy a trolley jack and get this thing sorted!