The Swytch eBike Conversion Kits have been shown at Eurobike 2022. Universal and Brompton-specific versions are available, turning your regular bike into a pedelec with a top speed of 25 kph (~16 mph) or 32 kph (~20 mph). The battery, providing up to 50 km (~31 miles) of range, is housed in the Power Pack, which weighs 2 kg (~4.4 lbs); the motor wheel weighs 1.5 kg (~3.3 lbs).https://www.notebookcheck.net/Swytch-eBike-Conversion-Kit-is-a-lightweight-device-with-a-top-speed-of-32-kph.636159.0.html
Price?
the figures are pure fabrication. A 2kg battery would be approx 9Ah if that and would get you maybe 10 miles on the fat, 15 MAX with more human effort.
My only comment is that the Swytch bike conversion does not work on all bikes as the Swytch team continue to say, but then deny when you begin the process of buying one. They only work for tires sizes 28 or larger. Most road bikes in the US today are not compatible with the Swytch conversion kit. Please relay that to your readers.
I put my name down for one in Feb 2022 paid and selected what I wanted in June and expected delivery July. I am now told my wheel may be delivered by September and the rest within two months after that or maybe not. I think I will ask for my money back as this is very poor.