car experts, please advise.

I've narrowed my search down to three cars. I've spoken to all three dealers and they've all agreed the same price (£600 plus mine p/x), so I'm in the position of picking between them.

I think I know which one I'm going for, but I've still got some doubts.

The cars...

http://www.autotrader.co.uk/classified/advert/201044372324522/sort/priceasc/usedcars/price-to/1000/seller-type/trade_adverts/price-from/500/make/honda/radius/100/postcode/m218ux/page/9?logcode=p 12 months MOT Honda Civic, reliable, big.

http://www.autotrader.co.uk/classified/advert/201044372101110/sort/priceasc/usedcars/seller-type/trade_adverts/price-to/1000/price-from/500/make/mitsubishi/radius/100/postcode/m218ux/page/3?logcode=p - this one is MOT'd till August 09.

http://www.autotrader.co.uk/classified/advert/201041370686493/sort/priceasc/usedcars/seller-type/trade_adverts/price-from/500/price-to/1000/make/volvo/page/4/radius/100/postcode/m218ux?logcode=p - this one has 12 months MOT and is about a thousand airbags. I watched that traffic cops programme last night, so airbags are important.

On paper the Mitsubishi looks the best value and will be cheapest to run BUT...I'm suspicious of it. It's recently MOT'd, youngish and is a low mileage diesel. My gut says someone has got rid of it for a reason. Why would you MOT your car then sell it for cheap unless it was going wrong? Either that or the dealer MOT'd it and now can't shift it. Either way, hmmm.

Cheers in advance for the help.