It's funny. I look at the UKPK and think "that looks nasty and pointy and dangerous", but it's legal. I look at the Spirit, Rebar, Wave etc and thing "that looks useful, tool-like and non threatening" but it's illegal.
Assuming I got a policeman in a good mood I think I could probably get my Wave through, I have quite clearly spent a lot of time and effort improving it's ability as a tool, but it's certainly not a given. What is a valid reason for carrying something? If I take my Wave, it's been used for countless things that I wasn't expecting to use it for but I'd struggle to articulate that if I was stopped.
"Well yes sir, it's a very useful tool. I'm known as a bit of a Mr Fix It and this is my go to thingy. I've used it for all sorts, like fixing candle sticks in church to helping a guy that crashed in to the central reservation and couldn't drive his car away." "But why are you carrying it *right now*?" "Well, just in case something like that crops up" "Oh really..."