I can see that such an attack could prevent the panel from alerting a monitoring company. But from what you say, an attempt to destroy or disconnect the control panel should trigger a correctly installed bell (which I am mounting externally).
That's great, as it will simplify my setup, and mean that I can put a cheaper keypad in the cupboard with the panel (rather than a designer one that is to be "on display").
My flat is not huge, and I am just trying to protect against petty thieves, as I doubt anyone more serious would find much to justify their efforts.