Cheers for the info.
The link below says the following - is that rubbish then? I'm not questioning you, I just like to learn how things work!
"Can I blow up my USB device? In short, no: You can plug any USB device into any USB cable and into any USB port, and nothing will blow up — and in fact, using a more powerful charger should speed up battery charging."
In terms of how chargers work, I always thought that damage could only be caused to the item that needs charging if you used a charger that was too powerful for it. In my simply mind, I see the device as passive, which will accept the incoming power if it's got enough current, but if not, just do nothing with it.
PS - when working, the phone does charge up so I think it must have more than 100ma and therefore must be a charging USB port.
But yes, ordered a cig lighter one off amazon this morning.