Rights?
Knowing your rights makes no difference, the police arrest first, then find a law to fit.
If all else fails they'll lie and say it was a public order offence, your word against theirs. No comeback.
Lets have it right, the average plod on the street joined because they like telling other people what to do, that they don't have the intelligence to be able to interpret the law (even after guidance from the home office) is a secondary consideration.