Well I decided to buy a dedicated USB STLink V2 adapter off eBay for Watch 2 (http://goo.gl/urzxxj – As with all eBay links, it will expire!), for a ridiculously cheap price of £3.11. This is pretty much just the front section of the STM32 discovery board in a standalone dongle, by using a standard 10 pin female header and my 2mm JST connector, I’ve made a specialised cable that connects the watch essentially directly to the USB port.

As you can see, a 10 pin female header, some 10 line ribbon cable and a 2mm JST connector connects the watch to the dongle.

All of the required connections are present and plugging the watch in with the above configuration allows for easy programming!