Proponents of extreme programming claim that by having the on-site customer request changes informally, the process becomes flexible, and saves the cost of formal overhead.

More than 90 per cent of customers requesting holidays had resumed payments.

The project was started as a customer request for an ultralight category scale replica of a fighter and was later offered as a commercially available kit aircraft.

Providers will also be required to offer a 12-month contract if customers request it.

Auctions can also include some plates that are specific customer requests.