After looking on YT at a video posted somewhere here, I noticed a video called 'Mark Knopfler on Guitars' and also downloaded that.
Finally I've got around to watching it and thought I'd mention it here in case someone else in also interested. It's not at all classical but features Mark sitting at a mixing desk talking and noodling on some of his guitars, both acoustic and electric and showing some little bits of his music. It's around 15 minutes long but worth a look. A google search should bring it up quite easily.