Never had a caravan before and have seen one I like on ebay, 2005, so pretty old. Private seller with a limited no of vans. No CRIS document, sold as seen.
1. Is 2005 too old?
2. Can you do a CRIS check, is it worth it?
3. Is there a way of getting a 3rd party to check it over.
As has been said, the seller is NOT a private seller, he is a trader and cannot sell "as seen".
As far as no CRiS document goes, he may not have the actual document BUT the van, if a UK made van, WILL be CRiS registered as that is done on the first sale of the van back in 2005.
As you have never had a van in the past and therefore would not know much about them, with any purchase you should get a Approved Workshop engineer to give any potential van a pre purchase inspection.
Any owner refusing to agree to this inspection has something to hide,,,so dont walk away,,,RUN.
Always ask for a recent service record including damp report, if none available, then a pre purchase inspection is essential.