The figure of £28,000,000 in deposits taken rings a bell from my previous mention of the failed Elio Motors company.
That was the amount taken in non refundable deposits by that company, too. Sadly, in that case, it was mainly taken from people on lower incomes who were promised a radical design of 3 wheeled road vehicle, which would supposedly undercut everything else on the market. Prototypes were made, but there was difficulty with the legislators, radical design changes were made, the purchase price keep going up, but there never was a working factory and not one production vehicle ever appeared.
I was initially very enthusiastic and very interested in buying one of these little cars (although I always knew the stated mpg figure was over-optimistic) but it very soon became apparent to me that the production timescale just being stretched further into the distance. In reality it turned out to be a crowdfunding exercise for an engineer with a vision, rather than a business with a realistic target. It became a race to find more punters before the business went bust and it failed. The whole thing was regrettable. All the punters lost their deposits and the company owners eventually received a large fine. I understand that the company is still aiming to produce vehicles, having changed to electric power, but there is still no sign of any.
I’d love to see Hill Helicopter’s design come right but I just think the targets are unrealistic, for reasons stated above.