Nice story but the Pugwash story may be hogwash. It is said that there are no recordings with said characters in the story (if any recordings). The myth might be true (?) if the unrecorded episodes were the first few and the BBC realised they had been had But in such cases the scripts would have had to be filed. Apparently there was a character called Blake or somesuch hence the myth.
Parity failure - how odd! they did have error correcting codes in those days, one was called the cat-o-nine tails. .