15 flights a day on weekdays with F100s. That's 1500 seats in, 1500 out per day. They will need something like 70% load factor to break even, say 1000 people per day. In autumn and winter, in a sparsely populated part of the UK with a fairly low propensity to travel, that sounds optimistic for a start-up with no public profile at present.
I hope I'm wrong, but I'll give them 9 months, unless that is, they've got backers with huge pockets or have some brilliant tricks up their sleeve.....