Yes, that's right SWBKCB. Although many of us might agree that the rules are harsh, Jet2 have exhausted all of the legal appeal processes and they now have to comply with the law. That includes a six-year limit on claims.
You can't blame CAA for seeking to ensure that all airlines now comply with the law.
Jet2 mustn't get a reputation for being recalcitrant - once you get such a reputation it's really difficult to shake it off, as Ryanair know only too well.