RR rear bench middle seat any good?

[PhilboSE]

I'm strongly considering getting a new RR, but during the time I'll own this car I'll have 3 hulking teenagers and the middle seat of the rear bench is really just a glorified armrest. We do long journeys in our "big" car; is the middle seat good enough for a teenager to sit in for long periods?

Must admit I was pretty disappointed in the rear bench seat layout; if they did the LWB with a forwards/back slider and an "equal 3" seat rear bench it would be perfect for us. Everything else about the car is perfect.