I've seen this on E bay. Im heading down London to take a look at her. Hoping for a test drive, you know what them london lot are like.. don't want to endup buying one with a loose box!
Things to look for:
Loose box which youve already mentioned
Have a good look at the undercarriage, give it a poke if necessary
Check the back box for strange smells
Ask if its been serviced regularly
Check for signs of abuse
It might be worthwhile giving a mate with more experience a go for a second opinion
Good luck
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