"I don't think ANYBODY arrives at LHR at 0430 in any kind of airplane."
I'm sorry this is not true. First landing is allowed at 0432 - I've been there and no we didn't go round the hold! - and aircraft with night landing slots (before 0600) are allowed in obviously. The rush after 0600 is for all those without night landing slots and with fast flight times inbound it becomes a game to judge what time to arrive at the holding pattern to ensure the shortest delay.
ATB