Thanks very much for that. I didn't actually realise the 2nd point. So just to clarify, anyone can buy a second hand car, say they don't like it (or lie about a fault that is intermittent) and return it within 30 days to get their money back (minus a few hundred for wear and tear)?
I actually went today told them about the boot problem, it wasn't playing up so they just said it was fine and there is nothing they can do. I have left it with them though as they need to get the Hybrid system looked at, so balls in their court now. I also got them to a sign a document saying on this date (within 30 days of buying the car), I alerted them to the above problems, so I have some proof if this ever goes to court.