I imagine there will be some at the Pathe site. It's changed its format since I first came across it so I'm not sure how it works.

Wales set up a National Film and Sound Archive a few years ago and there's a fair bit of BBC stuff there. As gret suggests, they wiped too much, but in the early days of tape it was a reuseable resource so had to be recycled - particular in public broadcasting. I don't know if any of it is available online. A few bits and bobs from the Welsh folk museum may come online eventually; they're working on making it available at terminals within the museum's main gallery and the curator in charge is very 'into' IT so ... there's hope.

sian