Like you said yourself spottilludrop, you've flown with Jet2 once, and not again. When was this if I might ask? As Brigantee has very correctly stated, the 757, albeit the remainder of the fleet has had a complete refurbishment, and even the old-timers are still looking well for their age. You say 'the aircraft interior was falling to pieces with gaffer tape holding it together', thus making me assume you haven't seen the new interior, meaning the last time you flew with them was like 2008!?
The whole fleet now is fitted with the slimline seats, which I might add makes them look fairly smart and modern, quite the flipside to what you describe.
The Low Cost Sector is ever changing. Alot has changed in the last 8 years