OverLander.co.uk Batteries

Have someone used or heard about this UK brand? http://www.overlander.co.uk? They look pretty legit and some battery specs are off the roof…

For e.g. this 22Ah 20C Continues 440A Burst 770A… https://www.overlander.co.uk/media/downloads/datasheets/22000_20C.pdf

I’ve had a look at them as I’m interested in high mah batteries and got a few replies saying their stats look good. As far as I’m aware, though, they don’t have much recognition and I struggled to find reviews.