I'm sure that's just a seating area and they have another two lounges/sitting rooms at the front of the house.
One of my friends has a huge house, but not as big as the Ingham's new house but still large with two living rooms, dining room, kitchen with a dining area and lounge area, 5 bedrooms etc. It's OK being able to afford the mortgage but the cost of running the house is huge! I'm not just on about gas and electricity but they have a cleaner and gardener as they can't keep up otherwise. Council tax is huge, so is things like mortgage insurance, building insurance etc and the maintenance costs soon add up. Just little things like window cleaners, two boilers to service, guttering being cleaned, decorating isn't cheap and say goodbye to doing things like treating your fences yourself as there's just too many. Even the most motivated person not having to go to work would find it basically a full time job trying to run the house themselves, especially around parenting. Hopefully they've considered all this as houses can just become money pits.
I've got a decent sized four bedroom house and we often considered about buying a bigger house but I honestly don't think I'd want all the extra work and costs that comes with it.