Didn’t realise you’d only paid £7, that is hardly worth worrying about. Most are £20 odd, so with another £15 + postage for this light, the overall cost just starts to add up, was what I meant
TBH all the batteries sold on these cheap lights tend to be poor, as AlexSimon says above they used to be better but have tailed off (nose dived) in quality since. If you pop the battery out of the bag, you might find the battery is plastic wrapped but has waxed cardboard ends, these will leak unless you seal the battery in a plastic bag (or better), so it might work fine but the overall quality is poor (is my point)
I like the solarstorm X2 units, & think there great value but from a reliable/reputable (localish) supplier you can return the unit to, if it turns out to be fault. Is my current recommendation, with the proviso that a better battery may need to be sourced.
Torchy (Big_f_d_d on ebay) had some dual XML unit for £40 which I thought worth a punt but have seemingly sold out, so other than SSX2 or light that cost £100+, there’s not a lot I can think of off-hand in between, I can happily recommend. So by all means give this unit a try, just don’t come crying to me, if it turns out to be another dud 😉