White Night WK767 Problem with microswitch on water reservoir?

The reservoir which collects the drained off water connects to a micro switch, the heat rising from below has caused this to distort, I have stuck something to the end of the plastic tank, this cured the problem for a couple of months but it has now distorted more so the switch has sunk back so far that it almost has no room to work, I can't find a supplier of a spare, and even if I do I suspect it will last no time at all unless I can protect it from the rising heat.