Nether Winchendon, Bucks.

You picked a good one from your collection then, as the sky really makes the picture here.

Why did you have to hold the camera up high?

To get more space between the top of the wall and the buildings behind it. Ideally the camera would have been positioned even higher.

One of the advantages of bus window shots. You could try a pogo stick, I suppose.
imgur.com/xSZyAzr

No double-decker buses, to my knowledge, pass that particular spot. But if I were ever to go there again, and were sufficiently determined, I'd take a tripod, attach the camera to it, and angle the rear screen so that the image can be seen from below, and set the self-timer. I'd then extend the tripod's legs fully and hold them and the camera high above my head, and take the picture. Several attempts, however, might be needed to get the composition right.

I'm not as flexible as Rowan Atkinson, but I'm much funnier.