[Stooky Bill]

That doesn't say which or how many transponders they signed up for in 2021, just that in that year the BBC were one of the many broadcasters they leased space to.

It'll be whichever ones were due to expire around that time, whichever they are. They were taken on over time as the BBC increased their satellite requirements so will all expire at different times. They haven't kept the same transponders since 1998, some have been changed and given up over the years