Hi, Duncan, welcome to the board
Now, this is what I call a challenge - how to recommend the FRV, without sounding biased!
Well, the way I see it, most of the new MPVs can accommodate three car seats in the middle row. The traditional 7-seaters will all do the job you seek, and the only real issues are whether you prefer to sacrifice your boot space for seats & if you are happy with putting passengers in the boot(!)
The advantage of the FRV is that you
always have space for six passengers, and you
always have a boot (which can take a pram and a weekly shop - that's coming from a five-person family, like yourself

)
Regarding the spec, I would always try and get the highest, with the most amount of toys as possible, depending on your budget, of course. The gadgets are what will keep you entertained, and make your driving life that much easier. I have the sat-nav, and have found it invaluable (not to mention convenient - no need to remember to charge or bring the sat-nav, and the security that a built-in stereo offers cannot be beat).
I have the diesel, which has a slightly lower top speed and acceleration compared to the 2.0 petrol, but I bought it for the efficiency anyway. Choose what you think is important - if you value speed, get the petrol. If you want value, then get the diesel.
I guess I have written too much, so I'll leave it for now. Feel free to ask any more. Good luck, take a test drive of all the cars, and let us know what you get. Enjoy.
Oh, by the way - if you're interested, if I hadn't bought the FRV, I would have bought a Ford SMAX
