Thanks for the replies so far, some useful information.

Bit of an update, tried to call the collections aganecy today who trade under the name of northwest collections and recoveries, the phone rang about 8 times then came up with an answerphone mesaage welcome to the 02 messaging service, strange?

I then phones the guy who visited whilst i was out. All they have been asked to do is deliver the questionnaire and at the moment have no interest in the car themselves. After a lengthy chat with the guy who was very helpfull, i explained i had hpi'd the car prior to buying it and it came back clear, He said that i took all the precautions i could to make sure the car was clear from any finance etc and said i have nothing to worry about.

But what should i do with the questionnaire? I dont want to be giving out all my personal details eg job title, company i work for etc when i cannot see how there is finance on the car if its come back clear twice, with a 5 month gap between checks.

What action should i take next? I have done a google search for the company but cant seem to find anything bad about them, scam etc