OK, so I did the obvious and called Philips. The answer they gave me was 12V, 500mA and positive inner, negative outer. So, now I connect a power supply (actually the mA is higher, but I understand thats OK) and now I think I have another problem.

According to the diagram the charging LED is a large area at the front of the cradle. I appear to have two small green lights (LEDs), one at either side of that. Is that correct or have I got another problem? (The infamous fuse)