very interesting but IMHO there seems to be one big flaw in their plan:
For a cheap jet to be operated cheaply, it needs to be flown by its owner, otherwise the cost of professional crews will kill the economic proposition (for the numbers they want to shift). Professional crews' job is to fly and keep everyone safe. The owner who buys a new sub £1m jet like one of these will be thinking he can use it every day like the car, so he will use it to make his business life easier. How can a time-pressed businessman fly safely to his meeting, concentrate on the meeting, then fly safely home again, regularly. Sorry but either be a top businessman then relax/work as you travel, or be a professional pilot and relax when you're waiting for your passengers.
I don't think you can mix the two and keep the business aviation safety record as high as it is today. Fatigued owner/drivers flying single crew in a fast jet in crowded skies late at night in grotty weather? I think I'll stay on the ground.
And as for the idea that 1000 of these will quickly create a shared air taxi network - well no one's done it on the ground yet with cars in city centres, so that is cloud cuckoo territory at £1m a piece.