Shall i just snip the wires off at the base and tape the remaining bit up?
No, the circuit needs to be complete to keep the warning off. That's how it works. As the pad material wears it eventually meat the disc, this wears through the porcelain and breaks the sensor circuit. Disconnect sensor/break the sensor wire or circuit/wear through the sensor as designed, all bring the warning on.
If the sensor is connected up and plugged in, but not fitted to the calliper it should never bring the warning on. If the warning is on under these circumstances then the electrical circuit is broken for some other reason than a worn through sensor due to pad wear.
In which case remove the sensor and find a spare piece of wire, like house hold flex, to join the connections in the sensor socket.
If the warning is then still on, then there's an issue with the car loom.