I get the feeling that a lot of the people who have paid the £40-£50k deposits for the HX50 won't ever decide to buy one. Some are just "speculators", others their circumstances would have changed since they paid the deposit (ie bought something else, or dont want a heli any more) and/or they will decide to "sell" their place in the production queue to someone else
I understand that Hill requires 45% payment for any aircraft a year before it is built, and the remaining 45% three months before delivery.