Does anyone know anything about these chargers?

Looking at the ad its a generic unit from China without a CE mark and no DC detection.
I suspect this is not upto UK safety standards and will need a minimum of of a DC detector to meet current regulations.

I've seen a number of generic chinese electronic things in another field and they rarely conform to EU/UK standards and are often a hazard.

Then if customs bill you its duty + 20% vat on top of the price.
You need a spark to install and to notify the DNO when installed.

I must admit I liked the Switch mode PSU where the Switching transistors had not been de-burred on the mounting holes and the burrs had penetrated the mounting insulator. Now as this was live why did it not blow the fuse / fail QA.... Duh the earth lead was detached as it had not been crimped properly. - This was in a sample product with the potential for substantial numbers and CE marked.

Caught it before it killed anyone and persuaded the MGT not to deal with this cheap shite company, difficult as they were always after something cheap.

Its worth knowing what the CE mark should look like The little amp listed above shows its ce mark in one of the images and it is wrong.