Well spotted James
Well this is an amalgamation of two manufacturers products.
English Rose kitchens were, as far as I know, the first UK manufacturer to produce fitted kitchens from what could be described as modular units. Produced from the late 1940s to late 1950s (maybe even EARLY 1960s)they were the absolute acme of style and designe at that time, where to have a cupboard with a sink and drainer (stainless steel or enamel) built into the top was just about as much as you coud hope for in a property. The units were of metal (aluminum I think) construction, manufactured by a former plane manufacturer. Considered very collectable here in the "retro" market there is still a great deal of it around.
There were a wide variety of units available, with even matching fridge unit, undercounter and unusual for the time, and I recenly saw a freezer as well - almost unheard of then in any context never mind as an integrated built in.
This is in that same catagory as "built in" split level oven and hobs were not really seen here until the very late 1950s where this, inspite of the 13amp socket looks rather earlier. The controls indicate that there would have been a four ring electric hob in very close proximity as well.
To answer Laurence's question the grill (broiler) is in the first compartment under the control panel. Underneath that is the oven and under that a warming drawer - this feature was NOT unusual in cookers (ranges) at that time, and indeed the "workings" of this unit where probably based on a freestanding cooker of that time.
The top row of knobs look to me like they would have controlled the separate hob. The LH switch is for the adjacent socket (switched sockets are almost universal here) with oven temperature next. The great big knob is for the oven timer, and the knob to the right of that for the grill. The small RH switch was for the warming drawer. I have no doubt that a unit like this would literally have casued gasps when seen.
It is unusual that it requires a 3 phase supply as it is very rare for this to be supplied in UK domestic housing. The three fuseboxes in the bottom cupboard are unusual as well as normally there would just be a single "line" coming from the main fusebox - and the electrical load of this unit would not have been significantly more more than for a normal freestaning cooker.
Revo is a name that disappeared in the late 1960s having been around around since the 1920s. Latterly they were part of the AEI group (Hotpoint) and may even have manufactured cookers under the Hotpoint name - although these are not that common.
Al