Any question answered...

You missed out, it's about 5 mins from my work, you could have done a couple of laps after dropping the charger off..

Ah, should've done that. Was keen to get home though. A 27-mile day of running errands and getting soaked in the storm = needing a cup of tea. Again, huge thanks for the loan...

4.134mm will just miss the internal peaks on an M5 female thread, 4.019mm will take everything but the threads off the inside of an M5 male thread.

tl;dr: Use a 4mm drill bit

A 4mm you say? I think I've got a bit that fits that description.

Coming up: a new pair of shoes after an unfortunate drilling accident...