I don't need to extend the collet/chuck, there's ample room above the table to change bits and I can easily press the shaft lock pin from above too.
Thanks for the advice about unplugging. In practice it's unnecessary because the NVM switch is extremely positive and it's impossible to switch it on by leaning against it. The stop button extends outwards above the start button, so even if you pressed something like a piece of wood against it, the stop button would be activated first.
You really do have to press quite hard with your finger to turn it on, so you really would know you were doing it. If it showed any sign of being faulty, I would replace it.
The main issue is that it's not possible to unlock the shaft locking pin from above the table. I can see the point of having a lock if the router was free standing, because the power switch could get pressed on by mistake, but under the table it's just inappropriate as you can't get to it without opening the cabinet door.