The YTV ORACLE processing has now finished (50,000 VBI frames!) and can be found here: http://teletext76.no-ip.org/ytv-19900915
Adding more VBI frames seemed to become less effective over time - it might be that the deconvolver always interprets certain characters incorrectly, and these reinforce themselves over time.
I've started another grab processing: it's from the same tape, and is the horrible cyan Ceefax design from when BBC News (I think) took responsibility of it. I'll check this when teletext.mb21.co.uk comes back up. You can see this here: http://teletext76.no-ip.org/bbc1-19900915