Originally Posted by Globaliser

In the Arrivals Lounge, as a passenger who's arrived in First you would be entitled to use the Concorde Breakfast Room, as well as all of the other facilities in the lounge. There's table service in that room, rather than having to serve yourself from the buffet, and you wouldn't be sharing a long table with others.

The HEX transfer is free; the Tube transfer is free if you have an Oyster or contactless card.

The dedicated lounge lizard would then crawl between all of the T3 lounges for a number of further meals of different kinds: Best T3 OneWorld Lounge

Of course, there will be others who would suggest that with 7 hours between flights, there's time to escape from the airport altogether if you wish, perhaps for a quick trip to Windsor.