Hi. I've got the 2400w version, and replaced the red/green button switch with a plain on/off rocker switch. Has worked a treat since 2008. UNPLUG the power before you remove the "control panel". Mark the wires attached to the switch, unlplug them and pull the switch out. Try Maplins for a replacement, just make sure the wattage rating is at least 13A (your mains supply), and the "form factor" (how it fits the panel hole) is correct. Unless the motor fails (unlikely), you can raise two fingers to B&Q and keep using it indefinitely: the electrical parts are common, obtainable from almost any high-street electric/electronics supplier.
DaveDawg, Devon
October 2012