Hmm - that's a bit dodgy.
The Edinburgh Tattoo BBC coverage is recorded over a couple of nights I believe and then edited, and rather than as-live commentary I believe they do post-even commentary in a VO suite.
The show went out on Monday Aug 27th (August Bank Holiday - a public holiday in the UK) on BBC One, as it appears it did on BritBox, but the Tattoo itself ran from 3rd-25th August, so had finished before the show TXed. (I believe the recordings were made approx 10 days earlier...)
The show may have been streamed on BritBox at the same time it was shown in the UK, but the event coverage wasn't live...