Whilst I feel very sorry for the people involved, and for the possibility that the Vulcan may not fly, you do have to ask yourself "Am I being taken for a ride?"
I'm sure that you are not. However there comes a time when enough is enough, and that giving "Just anover fiver Guv....." might simply be too much, regardless of how much you may have already thrown into the hole.
I wish the Project the best of luck, but you must understand why those 'Tight B@stards' may no longer wish to part with any more money. Their accounts are not always overflowing...