It will probably be hard wired in. So I would get an electrician in to remove it and put in a power point and isolation switch for new oven, to meet current standards

Thanks. How do you think they’d go about moving all that plaster? Would they have to put a new plaster wall in?

you will be able to find out whats behind the wall by first going into the room next door to see see if there's a recess from the other side and/or going up inside the roof space to look down from above to check if the walls around the oven are supporting the roof or hiding a chimney or some other mystery but if the house is not very old it's probably just a timber framed section with the oven installed into the space instead of the more standard technique of installing the oven into a kitchen cabinet..but, after an electrician has removed the old oven it's quite simple to remove the old plasterboard and the framing if it's not supporting any roof and then the gap in the wall and ceiling can be easily repaired by a plasterer and painted ready for a new kitchen...BUT it's never a good idea to rip out anything until you have a clear plan of exactly what you want to do and the new kitchen cabinets, plumber and electrician are all ready for installation and that's probably better left until you live in a house for a while

Great, thanks

Good advice above. Kate it's not a strange design, it is a well built kitchen.