OK - So as per a comment of mine some time ago I finally made and fitted an Emergency Cut-Off switch, along with an integrated power board.
Here it is after fitting the switches, but before wiring up.
I had some ‘fun and games’ cutting this 5.2mm ply, not the least of which was a loss of calibration (home) midcut. So I had to start again after recalibration and line everything up by eye (about 2mm off). Plus my current router isn’t working out as well as I’d hoped.
And this is it wired up (and tested):
The light dimmer gives me really good speed control over the router. And with it I can switch back to the smaller router (that doesn’t have speed control), but otherwise seems to be better quality.