Thanks for posting your question here. Ebay did make some changes to the category structure within the Car Parts section recently and it tool us longer than usual to update them so, while I'm not entirely clear on your reference to "MVL", I'm curious if you may have been unable to find the correct category in which to list because our category structure was out of date.
We were just able to process the required category update yesterday so you should now be able to navigate to the current eBay UK categories from within Auctiva using our "Browse" and "Search" features and find all the other options that are available when listing directly through eBay.
I did review the Sell your Item form directly on the eBay UK site after choosing a Car Parts category but I did not see any references to "MVL".
If you are still having trouble listing your items, I recommend contacting our customer support team by mousing over the "Help" tab within your account and selecting the "File Support Case" option.