You may need to turn off (or un-pair) Bluetooth accessories that are currently using your internal Bluetooth controller, as they can prevent the dongle from being detected by the Continuity Activation Tool.
The end bit was key. turning off the bluetooth devices and then bluetooth, then firing it back up finally did it for me.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I did this in conjunction with https://github.com/dokterdok/Continuity-Activation-Tool/
The end bit was key. turning off the bluetooth devices and then bluetooth, then firing it back up finally did it for me.