I have just bought a car (Volvo) and the wife has decided that we must have DVD system for the back seats to keep the kids entertained, bear in my that the children are 2yrs old and 4months old

She was planning on getting the Volvo built-in system as there was a special offer. Only £1000 instead of £2000

However she finally realised that the screens are quite small, about 5.7 inches.
I am now looking for a good portable system with one or two large screens, at least 8 inches. Possibly bigger as the wife has a thing for big TV's (we have a 50" in the main TV room and a 45" in the living room!).
At one end of the range I could for something like this
Wharfdale from Argos. Main benefit its only £150.
Or I could go for this
Nextbase SDV-185S twin screen system. Main disadvantage is it costs £550 (which is still £450 cheaper than the wife's original suggestion!).
I would probably go for the Wharfdale from Argos but I don't like their returns policy anymore. Especially as I am not sure how well it fit onto the back of the headrests of my car as they are a very odd shape.
Any advice on a good system, with speakers (as I can't see my 2yr old wanting to wear a pair of headphones!).
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