Reliable barge that will take 3 child seats in the back

[brrapp]

My brother likes his barges and loves his current 56 reg Honda Accord estate. Unfortunately he and his wife are expecting a third child early this summer and he was devastated to find that in spite of it being a big car, it won't take three standard child seats in the back. He really doesn't want an SUV or Mummy wagon, just a big automatic barge with room for three child seats in the rear. Any suggestions?
Cheapish, less than £10000. Automatic. Reliable, he is very rural. Reasonable economy (30 to 40mpg) but doesn't have to be diesel.Preferably leather. He prefers Jap over German but not immovable on this.