John said: "Stock agencies - oh boy. I think they are generally idiots when it comes to image quality."

I don't think this one is, John. The first paragraph of their guidelines is all about how and why digital is better than film, and they suggest that instead of scanning old film images that it is better to reshoot them with digital.
And then in the section about sumbitting digital images, they make a rather condescending and telling statement:

"Despite all of the digital technology available, there are still some people who don’t use the FTP to send their photos and need to send them via CD, DVD, or Hard Drive. There are some special situations which require this like a very high number of High Resolution files to send or a poor internet bandwidth or just because the world is formed of all kinds of people, some even still buy film…"