Answers:
Yes. however, if cutting the plug top off an appliance, it may invalid the warranty.
also, the appliance would need to be connected to a fcu (fused connection unit).
Absolutely not!! if we don’t show up for whatever reason, there is zero charge to the customer.
An eicr (electrical installation condition report) could be done on the properties electrical installation.
that being said, there is no guarantee that the property owner would get a satisfactory report, and could highlight problems that would need rectifying immediately.
You would not need to go to your energy supplier to update this. a qualified electrician could complete these works.