Any warranty offered by any seller anywhere is only ever going to be as good as your ability to enforce it.
I think you'll find that the manufacturer won't get involved if the item was sold via eBay, the warranty isn't usually transferable, but by all means contact them, certainly worth a try.
If your seller is a UK registered business seller then you may want to consider a legal claim against them. Make sure that you print off the original purchase details and listing in which is states that there's a 5 year warranty. If you haven't done this previously you may be too late now.
