uk777mot

Hi. I would really appreciate if someone would help me with this situation.We have purchased a 2001 Chrysler Voyager 2.5 Turbo Diesel Left Hand Drive which was registered outside the Uk before ( we don't know which country) . It was purchased in the UK at a Car Auction , which came without any documentations or registrations , on the invoice there is a Registration Number as 2453CLF and VIN No is 1C8GYN4M21U130663. We've been to a Chrysler dealer which gave us the Multi VIN Summary Report ( It's the only information they've got in their system).We want to register this vehicle into the UK,have sent all the information we got to DVLA including : Invoice of purchase,Multi VIN Summary Report, NOVA Reference Number , MOT Certificate and a Headed letter from Chrysler Dealer with date of manufacture but the DVLA is returning all the documents back( for the 5th time) and they require a "Dating certificates provided by vehicle owners or enthusiastic clubs must contain date/year that the vehicle was manufactured and must explain what source of information was used to determine the date of manufacture.They must also include an explanation of how the source information was linked to this particular vehicle.Dating certificates must be originals on letter headed paper." Has anyone experienced this before and how can we get this information ? Thank you