DX (deal extreme) is a chinese website that supplies cheap chinese lights.
Magicshine was a “branding” for some cheap chinese light (like Fluxient and Solarstorm).
You can get another light head of the same type or upgrade depending on your battery, though if you upgrade to a higher output head unit your battery runtime will be reduced (obviously). There a good chance it will be a Magicshine ‘clone’ of some sort, they all tend to use similar connectors. The connector are a certain size but polarity of the connections are awkward to test
TBH unless you really want to save as much cash as you can, just buying a new light and battery might be the easy option. As your unit was a couple of years old, the battery will have deteriorated.
Lots of XML head lights are available on ebay (or numerous chinese sites), as well as this years popular dual XML unit (solarstorm X2). Just search XML in the ‘cycling’ category will help whittle it down to just over a thousand. You’ll pay a small premium for a UK supplier, but will receive it quicker than waiting for a Chinese/Hong kong import.
I have a spare old XML head unit I don’t need, but there so cheap to buy, it hardly seems worth offering it.