Does anyone know what time the first international flight arrives on a Thursday into Gatwick South Terminal?

I am expecting someone to arrive at Gatwick from abroad tomorrow at 7am and have no means of communicating with them and now there are going to be immigration delays but thought if their flight is one of the earliest in, then there may not be too many queues and they might still make their connecting arrangement, which leaves the airport at 10am. Any idea on how many other international flights arrive by 7am at Gatwick South Terminal on a Thursday morning? Thank you.