Same thing happened to me, the switch fell apart, RH exchanged it on the warranty but said the same to me as Susie, no further warranty.
This is the 20414 kettle that sits in a power stand, and the switch on the replacement kettle has just fallen off in pieces like the original one.
Look like a faulty design or bad manufacture (made in china).
The plastic material is very hard and so superglue is not an option.
Shame on Russell Hobs.
John, August 2023