Just for the record, this is what I managed to glean about the charging of the 9505 phone via the mains charger:
I found that if you disconnected the yellow (2.4V connection) charging seemed to progress normally. However disconnecting the blue (function unknown) made the phone switch on as soon as it was connected, but prevented it from charging.
The car charger is wired as follows, I didn't get around to actually measuring the voltages:
In fact I gave up the attempt to build me own charger and simply integrated the guts of the car charger into a box of my own.