Well, the 35mm Holga experiment turned out pretty much as badly as I'd expected. To the extent that Boots didn't charge me for developing the film and printing the only two - very shoogly - pictures they could see on the negatives. Most of the film was wildly overexposed, but there were definitely Things there if you looked carefully. For example, this is obviously some trees and a swan with a rose superimposed on them:
Boots lack imagination. But "sprocket" is a good word.