Replacing a gas cooker(gas grill) for a gas cooker(electric grill)

What you need is as follows- What have you got? No socket/outlet- you will need one. What socket/outlet will you need? Depends on the (electrical load of the appliance). What is the load of the appliance? You should (by law) be able to find this under technical specifications for said item, careful you take the reading for electrical systems within and not the gas as they also use wattage. Now use the wattage they give to calculate load (use an online calculator/app or chat to an electrician) so you get the load in amps. What is the load? A. If the load is suitable for a nearby circuit to be utilised (check with an electrician, this needs to take into account the circuit design and it's expected loading currently). Or B. Is the load too great so therefore it requires a separate supply. So there you have it, personally I'd advise if you want to guarantee that you don't at some point have to hire an electrician, then keep it all gas and get the plumber (gas registered) to fit it, also get a cooker that dosen't require the sparker /ignition to have a power supply.

Yes the information for which cable I.e 6mm or higher will be available on the description part of the cooker your purchasing

I doubt that your new oven would require anything more than a socket. A grill element alone is unlikely to need much more than 2kW so you can use the same socket you used for the current gas oven and grill.

Just check the speciation for the oven - it will tell you if it needs dedicated cooker circuit or hardwiring, or if it comes supplied fitted with a plug in which case you can plug into the existing socket