BAP, some eleven years ago I left a legacy airline to join Jet2, sure as you gain seniority in the legacy carriers your income increases significantly in comparison to Jet2, however it comes with the difficulties of long haul. Short haul in any legacy carrier is very hard work, usually involving multiple nightstops etc. Having joined Jet2 I have no regrets, with your experience you could join as a direct entry Captain and the benefits of a non seniority based airline are that should you want to branch into other areas (training, management etc) these positions will be available fairly quickly should you desire. The benefits for me are you rarely nightstop, yes in the summer you work hard, but due to the length of the sectors you tend to work less days compared to a legacy airline (more reserves and SBYs etc), you get home just about every night, the winters are quiet with extra winter leave options should you desire. In short I got my life back! It is a difficult decision, but if you live in the NW then I think it would really benefit your lifestyle, having commuted myself for many years it was not until I made the change that I realised just how much of my time was spent travelling or on SBY in digs!
Good luck with your decision.