They come with rubber bits to fit inside the switch gear so they disconnect. But positioning the box is quite key and too many wires have to be cut. And it's a lot of dosh for something I have a pretty good grip on (for now). I swapped a few mails with the guys - but all seems a bit unnecessary.
Notably they have dropped the price - I guess they are not selling that well. They also now have an inertia based brake light activator. But again these can be found cheaper.