It seems like a good device, like I say it does have some draw backs compared to a chip. It's mechanical so will eventually wear out, though it's supposedly good for thousands of miles, it's limited to 1.5x of your top assisted speed, it can't be tuned or adjusted and maybe the biggest draw back is your milage and speed will be inaccurate, also it will only fit certain bikes with disc magnets.
Here's the official website, though the "two wheel empire" is the UK distributor
Shop our mechanical e-bike speed limit increaser. Electric bike speed limiter removal. Designed, manufactured and tested in New Zealand. Compatible with e-bikes from Specialized, Trek, Giant and more. Easy to install and remove. We ship internationally.
nlscomponents.com