And re separate units, it's a small kitchen and battle for space.

Same here; the hob is in the scullery, but there isn't room for an oven there - you'd bump your bottom (and possibly need a bottomry bond) on the opposite cupboards or the fridge every time you crouched, and couldn't open the door properly.

So the oven is in what used to be called the 'breakfast room', in its old chimney.

Works for us, anyway.