You know what? I'm still sifting through all the photos I took. You've no doubt seen some of the low quality photos I took with my camphone, but I did have a proper digital camera with me too. It seemed like an ideal opportunity to learn more about the concepts of photography: shutter speeds, apertures, etc. Unfortunately, I had failed to take into account the nature of the challenge.
Taking photos from a bus is difficult. Firstly, it is moving. If you make a mess of a shot, there's no going back to have another go. Secondly, it is difficult to take shots through a window on a sunny day without getting reflections of seats, stanchions, etc. Finally, it may not seem strange taking photos from a bus whilst passing through a national park, but you get a lot of strange looks and half-whispered mutterings when you attempt the same in less touristy areas.
(Taking photos of buses is difficult too, for reasons of movement, strange looks, and also the fact that you've a tight connection and don't want to stray too far from the queue – but that's another story.)
In the meantime, here's my favourite quirky hi-res photo, taken from the X4 as it sped along the A45 south of Northampton.