I had this a few months back when I was looking for a 2005/6 mr2, went and viewed one that had low miles but poor paintwork, got there and it was pretty poor all round but was cheap enough (up for £2.8k) that it didn't matter went round the car with the owner and pointed out the dents/damage etc as you do, agreed a deal of £1700 as it was going to need a full repaint blah blah,
did the hpi check and turns out it had almost 2k of debt owing,offered to pay off the debt she said no I need the cash and its fine I will just keep up the repayments,

Think we had a lucky escape I don't usually bother to do data checks on older/cheaper car but think I will in the future