I acn only guess that it must be at least 10 years or more since the Vulcans were grounded, there can only be a finite number of pilots and even they must all be the wrong side of 50+. When where and how would these guys get there simulator / familiarisation/ recency as required by CAA / JAR even if one of the a/c was by some miracle to become airworthy.
Face it unlike the USA where indeed aviators do make their dreams come true and keep many types of a/c flying in the UK we have neither the time / places or official commitment. I site Concorde as the most recent example and today there a five that are airworthy this time next year there will be none.
Twenty years down the line what is the betting that some good natured soul will say lets get a Concorde airworthy. Dream on it will not happen for the Vulcan the Concorde and numerous other types.