I repair Dyson Supersonic Hairdryers, among other things, and the number one item that breaks when disassembling, is always the switch retaining pad. it is made of a material that gets brittle with years of use and the air blowing over it constantly. the holes in the original retainer have a very thin wall and crack.
i cant purchase these anywhere apart from AliExpress they are a ridiculous price. so I've designed my own. its not the same as the original one BUT it fits perfectly. the only thing you need to do is drill out the tiny holes for the 4 screws when fitting. i find that heating up a small set of tweezers up and using them to start the holes for the screws is a good solution.

The rounded edge of the part goes towards the motor end, this helps with the airflow getting to the heating element.

If this is useful for you please let me know, or if you have any better ideas then message me.