Re: "My keychain has 2 sizes each ..."
"As the law is written, any non-locking blade under 3 inches does not need a 'good reason'."
How about a couple of feet of fixed blade? And how do they define "good reason"? I use my aging Buck 110 (or old Schrade LB7) probably a dozen times per day, every day, and my not quite as old Leatherman Super Tool more times than that.
"However the moment you say it's for defence you are now breaking the law no matter the size of the blade."
What kind of blithering idiot would claim a pocket knife was a defensive weapon? People like that are more a danger to themselves than to anybody else. No need for plod, let Darwin sort 'em out.
Continuing the theme ... am I allowed to carry my walking stick? Mine is white oak, 7'2" by approximately 1.85". I forged iron caps for each end of it, mainly because I don't want it to wear out before I'm done with it. It's a comfy piece of wood ... When I ran across it, I knew exactly what it was meant to be. Comes in handy for stability in rain, mud & snow, and when I'm moving sheep & cattle around. Great tool, everybody should have one :-)