Sorry to hijack your post but I'm having similar electrical gremlins. Started 2 weeks ago after work I went to start the car and all the electrics turn on but the car wouldnt start/turn over. I have a 1.6 diesel automatic btw. I got a flashing glow plug light warning on the dash. I had to leave it at work and came back the next day and it started fine but on the way back just coming off the M3 the start/stop system didnt work and the car wouldnt startup again. I managed to roll down a hill and park up on the side of the dual carriageway and then started the car and got it home.
Since then I've had to drive it to and from work and I've had a start stop error message pop up intermittently. I've just been turning it off to avoid a similar instance however on Sunday I forgot pulled up at some temporary traffic lights and again the engine didnt kick back in. This time I couldnt restart and had to call RAC. They were going to be a couple of hours so I tried it intermittently while I waited and managed to fire it up and get home.
The following day I drove to work with no issues but when I left work again the car wouldnt start. Same issue with the glow plug flashing dash. Luckily a guy at work jump started it for me.
I've checked the battery and it's fine. I've run a diagnostics on it and I get thr following error codes P305400 starter does not turn me basically blocked or electrical malfunction. The fact it started with the jump makes me think it's an electrical issue. I also have an error code of B116229 saying selector lever park position lock switch implausible signal. I have had an error message for this once every few months but didnt think too much of it. My question is does anyone know what the issue could be? Could the selector lever signal issue be causing the starter issue? Anyone experiencing a similar
problem? Any advice welcome.