Good advice, thanks. If only we could rely on common sense from the plods like we used to be able to.It's quite situational aswell. So if the police get called in because secca have caught you and you are causing lots of trouble and getting aggressive with them, then having a blade on you is gonna get you in a world of trouble. On the other hand if you are pleasant and it can be seen that you are being polite and have a good attitude then it will be way less of an issue.
I actually asked this question on the r/UKpolice subreddit a while back, and the generaly opinion that as long as you weren't caught on a dark street corner where there was recently trouble, and the tool itself is reasonably sensible justify, then your gonna be okay. ie small SAK multitool or a smaller leatherman ie easier to justify as its got a wide range of uses. However a dedicated folding blade like a Spyderco or Opinel is harder to justify as its got less general uses, even know they might still be 'legal carrys'.
To be honest its all a bit grey, but don't be a tit, have a good reason ready and you should be okay.