If you didn't enjoy your journeys on 7524 and 7531 (both decent in my view), I dread to think what your view would have been if one of 7501-9 had been chucked on your X21/22 journey!
Unless you didn't enjoy them because of the passengers, which is fine
I had the exact same problem with my ride on 7530(?) a couple of weeks back on an X18 from Berwick...