I'm planning on moving to ****-cheap-Wales from this ****hole called Bournemouth. I was born here (Christchurch) but been away for years and the hometown I knew and loved has long gone. Wish I'd never come back
Anyway, I'd fit the switch and fuses etc first, then when the windscreen accidently cracks, tell Autoglass that it is a heated one. When they arrive- with the heated screen- just say it is supposed to be heated and you wondered why it never worked.....
Not that I'm planning any such tactic....