Here you go.
https://www.ebay.co.uk/itm/323199246084
https://www.amazon.co.uk/Downtube-Ba.../dp/B01JPM58PU
Your motor is a direct drive (gearless) unit. Good for speed,.Quiet. Simpler. Less good for hills, Needs a bigger battery to do well. I personally like geared motors. Less drag for pedaling, if you like to do that. The battery is a better fit for a lower power motor.
Here is where UK experts hang out.
https://www.pedelecs.co.uk/forum/for...discussion.42/