Time limit for Vat reclaim

A colleague of mine who runs a business has found a number of legal invoices from 2004 on which he was charged Vat. He never claimed the Vat. As this was a genuine error what are the chances of him claiming now or will the 4 year time limit for refunds kick in?

He would have claimed the full amount as a business expense, so trying to reclaim the Vat now would mean revising his previous accounts and tax returns. Even id not over the time limit, it's not likely to be worth it.

4 years only. Like previous poster, its not worth it.