While the chances of the UK ever building a mini-monster like this is zero. It is interesting as a design study for getting big guns to sea. Why a mix of big gun and missiles? I have given this ship 15" guns. Using rocket assisted projectiles to increase the speed and range of the projectiles should mean that whenever a call for fire support arrives the shells should arrive in minutes. Using the longer range Tomahawk cruise missiles could take many more minutes to arrive due to their subsonic speed. The difference between life and death. The projectiles with a 15" diameter, with small steerable fins, would certainly give enough room for whatever electronics may be necessary for any given mission. This could include laser guidance packages where the laser designator would give the arriving shells awesome accuracy. Using the ships own drones would give it the spotting capabilty to support the big guns.
People say "Why build a dinosaur?". It is because the sheer power of a battleship will always give your enemy pause for thought before he commits the act of war. When you have a battleship parked off your coastline and you are literally staring down the barrels, the first thing you reach for is the toilet paper, the second thing is the peace treaty papers.
With the extended flight deck the ship is just on 700 feet, with a beam of 88 feet and draught of 25/27 feet. At standard the ship would be 24,500 tons with a full load displacement of 29,750 tons. Propulsion is modest, 4 shafts Integrated electric propulsion (IEP); 2× Rolls-Royce WR-21 gas turbines, 21.5 MW (38,800 shp) each, 2× Wärtsilä 12V200 diesel generators, 2 MW (2,700 shp) each, 2× Converteam electric motors, 20 MW (27,000 shp) each, wich gives a total of approx 80,000shp for a speed of 27 knots. With the Albion/Ocean types only making 18 knots this ship would be fast enough. The ship is not a monster but carries enough weaponry to be able to fulfill the roles asked of it. Armour is placed to cover the machinery spaces, shell handling rooms and the aircraft refuelling tanks. The UK's favourite 15" guns are fitted to the ship with two twin turrets carried forward.
With the advent of the QE class carriers the ship(s) would probably need to be faster if they were to act with QE's. This would require an increase in size to produce more power to match the QE's speed.