Re: Power Line Communication
Mine was installed by OVO as well, and it's clearly stated that they have a SIM and use a mobile phone data connection. Otherwise it would be fairly complicated as current Gen 1 UK smart meters communicate directly to the energy supplier. Gen 2 smart meters will have more features and will communicate with a centralised entity to ease switching between providers (but you can still keep your smart meter from turning dumb if you switch to a provider that uses the same brand of meters, like I did from OVO to Octopus recently as they both use meters from the Secure brand). This is in turn made more complicated by the fact that there are many different grid owners in the UK. In France, pretty much the whole country is on ERDF's grid (apart from Strasbourg, if I'm not mistaken - kinda how Hull has it own non-BT telephone network), so that makes thing much easier.
Oh, and the reason why they don't have to make an appointment or wait for an agreement to replace the meter in France is because the company owns the meter (like in the UK if I'm not mistaken), and they are usually in a tiny cabinet on the edge of the property, which can be accessed at any time (and by anyone as it's kept closed by a simple lock that can be opened with a screwdriver - or a flat pebble). They just need to give you a bit of notice, as they're going to switch off your supply for the change.