Mini One diesel odd ignition problem

Whoa, that sounds mighty familiar! Had a similar, bizarre starting issue with my old Vauxhall, although it was petrol, not diesel. The symptoms you are mentioning are very close to what happened to me. Key turn did nothing, engine would sometimes cut out out of nowhere, and on the rare occasions it actually ran, it sounded like it was about to cough its last breath. I'd check the simple stuff first, like your battery terminals and grounds, but it honestly sounds like it could be electrical. Keep us posted!

Interesting. So, with your Vauxhall, what exactly was the root cause? Was it an ignition coil problem or maybe something with the starter motor?

Yup, turned out to be a faulty sensor causing all sorts of havoc. The ECU was getting bad data, leading to the erratic behavior you're describing. Honestly, save yourself the headache and get it hooked up to a diagnostic tool. See if any fault codes pop up. Otherwise, you might be chasing ghosts! If it's not a simple fix like a fuse, you might want to consider taking it to a workshop.

Just wanted to close the loop on this ignition issue. Turned out it was a defective fuse, like I suspected. Replaced it myself; cost me about 52€. Thanks for your help with this!