I joined one of the largest UK charter in 2005 type rated and signed for a £2400 bond over a 6 month period to cover the company conversion training...no big deal!
6K over 12 months is slithly more but provided that you sign the contract with the intention to stay then what is the issue here?
Especially in these times where more and more pilots are looking for any temporary flying job just to keep filling their logbooks and paying their bills who will then move on when something better comes along it is completely acceptable to show some sort of commitment by signing this bond.
End of this discussion if you ask me...time to focus on what really matters as T & C, future outlook of Jet2.com etc!