A couple of weeks ago the Maxidot brake pad alert came on, intermittently at first and then permanently.

Changed the front brake pads at the end of last week and the alert is still on! Think i'm right in saying the rears haven't got a sensor on them, and they are fairly new anyway.

So could it be a faulty sensor? Can i switch off the sensor or do i have to change it? Is that an easy job?

Who changed the pads?

The sensor is changed at the same time as the pads as it is part of the pad, however if the wrong pads have been fitted then the sensor may have been bypassed or not plugged in correctly.

It is possible to turn off the brake pad warning with VCDS but TBH I can't see why you want to, with the correct pad and sensor fitted correctly the warning will go off anyway.