Over the years many things get lost, unfortunately. Up until quite recently things just weren't as well preserved as they are now, which is a shame. There are so many shows of which I would love to see bloopers and uncut material. Imagine outtakes from TNA for instance, wouldn't that have been amazing?
I would pay an indecent sum of money to see TNA outtakes--that would be possibly the most awesome thing ever.
Just the thought of seeing Gareth, Joanna, and Patrick screwing up, cursing (we know Patrick and Joanna do--I get the funny feeling an ex-sailor like Gareth knew some pretty colourful vocabulary
), and then laughing like loons makes me want to bounce around uncontrollably. I'd particularly love to see Gareth and Joanna doing scenes like the one in Faces
where he was pinching her butt and stuff--I'll bet they had a hard time shooting those.
As for Class Act, of course it's always possible stuff is socked away somewhere. But like Philippa said, they haven't been preserving TV the way they do now for very long--they used to wipe tapes, sadly! It's just that CA wasn't a major series the way things like AbFab and MASH are, so the chances of them treating it with less respect are pretty high. That said, there are trailers for the show floating around on youtube, and yet they never put those on the sets, so who knows what there is out there?
I wonder if there was anything in Verity Lambert's estate about it? She may have had something in storage that could have been uncovered after she died.