ImperialFighter said:

Given the amount of 'repeats' the BBC has been so fond of giving us over the years (some welcome, some not), I still find it incredible that there was a time where they routinely and short-sightedly erased some of their output in the past.

It's quite common sadly.

I was rewatching the Blade Runner restoration documentaries the other week and that team found all the film stock for BR, deleted material/negatives/FX footage etc on a big pallet that was marked for being destroyed. Luckily there had been a mix up so the final memo to burn it all had never gone through, and it was just sitting in limbo when they rescued it.

A read an article about a famous film Director in the early 00s who was going to do a director's cut/deluxe-DVD package etc for his film and found the studio had binned all of it without even consulting him. Years of his work and future profits gone. Wish I could remember who it was.