Mr Tartinton... don't quite know where you have got your figures from... but they are well off... the "charter" cost of a Boeing 737-800 from the UK to the Canaries and back is around the £29,000 mark... at 80 seats that equates to £362 per return passenger... so for a flight from the UK to mainland Spain, it would be a lot less than the £600 you quoted.
Nevertheless, with the economic uncertainty at the present time, I can't see 'Premjet' being successful.