If they're just getting one, which it looks like they are, it'll be interesting what contingency plans they'll have in place if it goes tech.
It'll be an expensive lease if all doesn't go as planned - shipping a full A330 load across 2/3 other aircrafts or leasing in another is not going to be cheap. I'm sure the company they're leasing off won't compensate a lot to them depending on the issues.
Don't mean to be so doom and gloom but surprised nobody has not mentioned this yet.
It could still be a good move for Jet2 though if it all goes smoothly - I imagine there'll be plenty of £££s for them and could change the structure of their business for future years.