As a BA 787 SFO I average about £5300 / month net on pay point 7 and I get 13/14 days off roughly every month.
The big advantage of Jet2 for me would be living up north, which I would vastly prefer for many reasons but not least because its so much cheaper from a cost of living perspective.
Trouble is, it sounds like a lot less days off and not that much more money to sit in the LHS.