You can't carry on trading under a dissolved company name - it's illegal if you carry on using "limited" (or the shortened version, "ltd"), which you are doing on your website and ebay at least.
As I understand it, if the cars (and any money in a company bank account, property, etc) were owned by the company - and you didn't choose to dissolve the copmany and therefore didn't move the ownership before the company was dissolved - then they're bona vacantia i.e. not yours any more. If they weren't in the companies name, then who owned/owns them?
http://www.bonavacantia.gov.uk/output/bvc1-assets-of-dissolved-companies-that-have-vested-in-the-crown-as-bona-vacantia-1.aspx