Total teardown and schematic of the Poundland GU10 LED lamp.

I decided to fully reverse engineer the Poundland GU10 lamp because it has an interesting LED driver that is based on discrete transistors.

I'm not 100% sure of the purpose of what appears to be a charge pump with a zener as a threshold arrangement. I can only guess that it's either part of the regulation or to protect against open/short circuit scenarios. Note that the associated capacitor seems to be pumped negative to the main transistors emitter, so if the voltage on it is too high it will effectively prevent the main transistor being turned on.