Just noticed another odd thing tonight. THe phone battery ran out on me while I was down the gym, went totally flat.
Came home, plugged in the wall charger and it's been charging. Go the message that the charging was complete and to disconnect, which I did.
At this stage, the battery indicator only showed two bars, as opposed to a full battery.
Left it for a minute or two, still no change. Switched on and off, and upon re-start, the battery is now showing full charge.
Dodgy software?