Why do you find it hard to see why it won't work? Dumping 900 seats per day into a city to city market which is already at over-capacity at precicesly the time the railways are getting their act together struck me as a dumb move? Remember, Jet2's pricing on this route is still at a rate which is less than cost. The idea is you fill the planes early doors and the hope the custom sticks when you move the pricing to something you can make money out of. If you're getting loads in the 20s with £9 fares, it's never going to work; believe me.
Plan A was to use the LGW slots for an LBA servivce which is exactly what they should have done.
loco