Doubt that Miles had the German data to hand when they designed the M52 in 1943...
Neither Bell nor Miles 'invented' the all-flying tail, they were used on some WW1 aircraft. The point is that Miles anticipated the benefit of using it on a transonic aircraft, and specified it from the outset. How Bell arrived at the solution is also not really the point, but they didn't apply it first and credit should be given where due (imho).
