Wait are these microwaves one unit, or a separate oven and microwave? Here in the states they're always separate, though sometimes a microwave might be above the stove and function as a smoke hood.
Something like this render from Best Buy is common enough. That's what I'd call a normal size microwave in either case though, just different mounting options.
I could certainly fit a microwave inside my oven, so they're not really too similar size here unless you get a moderately large one. In fact, that render only has a kind of weird scale, the gas range and oven seem about right.