OLight I7R provided battery (supposedly available separately but unable to find).
I have IMR 10440 (Efest v1), which are closer to standard AAA-length due to lack of protection circuit, and use these for almost everything that accepts the voltage. However it would be nice to have a (non-*Fire) ICR choice where the protection is preferred to prevent over-discharge. I purchased a LL M3R recently and it is a great little zoomie light; the included 10440 certainly seems safe and reliable.
Perhaps Ledlenser, LEDCO (UK distributer), or one of the stockists is willing to supply a battery for your tests, as it will undoubtedly help them with sales through association with the forums and your testing endorsement.
Failing that - if you’re willing - I’d be happy to send you my recently purchased one (still sealed in packaging); if you would be able to return it after testing?…