Hi Greg, I'm a bit confused - have you actually already ordered / bought this lens from the ebay seller, or are you still thinking about it? I can't speak for the seller, but here's some warranty info...
An item under a worldwide warranty *should* be accepted for free repair at authorised service facilities. Since you'll most likely be wanting Nikon UK to do any possible repairs, I'd advise speaking with them first to see if they would accept an item with a worldwide warranty for free repair.
Their contact details are here:
www.europe-nikon.com/footer/en_GB/foote ... tacts.html
In the meantime, I have a Nikon lens here on test and it has a yellow warranty in the box which is labelled as 'Nikon Service Worldwide Warranty', so they do exist!
An accompanying piece of paper explains "Your Nikon equipment is guarenteed against any manufacturing defects for one full year from the date of purchase. During this period, repairs or adjustments will be made free of charge only upon presentation of the Nikon Worldwide Warranty Card (Copy C, customers portion) together with the sales slip or other evidence of purchase to any of the Nikon service facilities listed here"
The list includes six authorised repair centers in the UK: Norfolk, London, Durham, Kent, Stoke-on-trent and Glasgow.
My lens was sourced in New Zealand, so I'd say if yours comes with the same warranty card, you should be fine. Just make sure you DON'T get a grey import, which will probably only have an Asia warranty if it's bought from Hong Kong.
Also beware that if you're buying from abroad, you may have to pay VAT and duty on its declared value when it comes through customs, which could be around 25%.
Let us know how you get on,
PS - as far as I understand, Nikon digital products including DSLR bodies are only offered with local warranties. For example a European warranty. I've no idea why this would be the case.