I imagine the fact the DVD is not out in the UK has rung alarm bells with the Insurers, they are likely to want to go over the whole claim with a fine tooth comb and ask for receipts / proof of ownership for all of the items and then check them.
They are probably working along the lines of this case
http://www.financial-ombudsman.org.uk/publications/ombudsman-news/42/42_ins_fraud.htm
If the DVD has been bought and you can prove this to their or the ombudsmans satisfaction then I would expect the ombudsman to insist the Insurers pay the claim. After all its not unusual and is not illegal to buy legitimate copies of DVDs that are not out in this country from other countries.
I would suggest you do all you can to prove you had this DVD, if your friend cannot access the ebay account is it possible to make contact with the ebay seller perhaps by looking on ebay and then asking them to confirm the sale / delivery to you.
Providing the rest of your claim is genuine and you can prove ownership of this dvd and it is a legitmate copy or you could reasonably expect it to be a legitimate copy then eventually you claim should be paid. Please bear in mind that the Insurers / Loss Adjuster will delve very deeply into your claim, it is very important that you do not lie as its likely thye will discover it and it can cause problems or the claim to be refused if you do