I suspected the liability issue. Maybe the company's legal department has said that to play it safe they shouldn't connect unless there's an RCD (GFI) present, although as this exceeds even the current requirements of BS7671, it seem over-protective. Maybe if it wasn't that, they'd have come up with some other excuse.

Anyway, by the time I left the lady was already on the phone to the company demanding that they now come back and take away the old cooker as agreed (and from the language being used, I use the term "lady" in a very broad sense!).

Bill,

Quote
They now request a Receptacle be there and they will have a Cord & Plug on the appliance when delivered

Do they ask whether it needs to be delivered with a 3- or a 4-wire cord?