By my calculations, the roughly 1.5m GBP per annum required needs about 25,000 donors to put in 60 GBP per annum each, or a fiver per month.
Doesn't seem like that many people out of a population of 60 million, lets say 25 million who earn so that's one person in 1,000 donating that amount of money.
I will confess that every time I hear from the various XH558 organisations it's either boom or bust, they've been going on about a wonderful summer display season and then suddenly with only a month to run they need another half mil!
Not impressed....