Indicator switch probs with ZD

[6Pak]

Hi Folks
My ZD was parked in a driveway on the weekend in the sun which has caused the indicator switch to warp and lose contact with the base plate which now means my indicators only work now and then. This is the second time this has happened since I rebuilt the car. Has anyone else had this problem and are there any tricks to avoid this ie heat shield in the column or an alternative part supplier other than rare spares.
Cheers