Will definately confirm who has first choice for this round.
I am pretty sure the BBC have first pick for every round, it's only the replays where BT have alternate first picks.
That’s correct - BBC have first pick in every round, BT have second, fifth and six pick. Third and fourth picks alternate round by round, as does first pick of replays in third and fourth rounds.
(Replays have now been abolished from the fifth round onwards and with the winter break coming in next season the fifth round will move to midweek.)
I think it’s the case in the third and fourth rounds that whoever has third pick from the main draw gets second pick of replays, whoever has fourth pick in the main draw gets first pick of replays.