Wikipedia says that each Rolls-Royce RB108 produces 2,340 lb of thrust at maximum. There are four of them mounted horizontally. 2,340 * 4 = 9,360
Normally, two Derwent 5s would power the Meteor T.7, with 3,500 lb of thrust each. 3,500 * 2 = 7,000. So this thing has more horizontal thrust than a normal T.7, in theory.
However the drawing claims that the fourteen vertical engines combined produce 26,320 lb of thrust, and 26,320 / 14 is only 1,880. 1,880 * 4 = 7,520, which is still more than normal, in theory. But, there is the fact that this aircraft will have more weight and drag than in its stock form, which will probably negate the small thrust advantage. The fuel supply would have to be very complicated and would reduce available fuel storage space in a craft that already guzzles way more gas than the twin-engine T.7.
Then, of course, the entire system of controlling all those engines would need to be very complicated. I would have to agree with Vick, GregP, and fubar that the aircraft is just not practical and it's a good thing it didn't get anywhere.