Power adapter limited?

It depends, I have seen some adapters that change the voltage and some that are only adapters that don't change the voltage. If it is a transforming adapter it could be overloaded by the light and that's why it may not be working. It also could be the voltage since the US uses 110 and the UK uses 240 and the led bulbs often use low voltage themselves and have their own transformer and you could be over powering it but I think if that was the case it would have burned out as soon as you plugged it in.