I'm sure there's a self-dependent work ethic that isn't necessarily instilled in school (which tends to be quite organised on behalf of the students, rather than by them) that a decent amount of working experience helps with a lot.
I did my first degree after a short apprenticeship, and must admit to enjoying many of the distractions available when in your early 20s! This probably explains my 2:2.
After a few (!) years doing real jobs in the aircraft industry (probably on the same aeroplanes you were on) however, I decided to spend a chunk of my spare time doing a Doctorate. In many ways I found that I had a much better understanding and work ethic behind what I was doing than I had as an undergrad. So, although it took a lot longer, and certainly had its frustrations, I found a PhD in my 30s, much easier than a BEng in my early 20s.
G