I don't want to belabour the point but I'll paint a slightly different scenario to the OP.
I arrive at someone's property to do some work. I notice they are wearing a rather tacticool neck knife (not my cup of tea). As someone interested in knives we talk and they tell me about their collection of knives, air guns etc. As I'm leaving they ask if I'd be interested to see their knife collection. I say yes so the owner invites me inside and proceeds to pull out a very large 'Rambo' style survival knife (not my cup of tea either) we talk some more and they tell me how great this survival knife is and how it could be used in all sorts of exaggerated ways. I have in my toolbox some bushcraft knives. A mora, a wood lore clone, a nessmuk (maybe choose 3 knives you like) They are all sheathed and in a separate compartment to my other tools. I explain to the owner the different merits of the different knives and how each is suited to particular uses. I also talk about the search for the perfect one knife to do everything at camp and the pros and cons etc. I get my phone out and show videos of feather sticks and batoning and skinning a rabbit etc. The owner is polite and seems interested asking questions etc. We leave on good terms.
In this scenario am I reporting the owner to the police? No obviously not, the person is interested in things that aren't for me but that's a question of taste. He was on his own property and at no point did anything that warrants suspicion from me. He may have exaggerated or lied about his prize survival knife but again that's not unexpected in the circumstances.
However what if the owner reported me to the police?
Would I be happy? No.
Would he have been within his right to report me? I'd say obviously. I went on his property with knives that I had no business taking and which under current laws are illegal (when I say that I don't mean the knives are illegal I mean the carrying of them in public is.).
If/when I get a visit from a police officer it is then down to me to explain my good reason for carrying the knives.
We could go further and I could give any number of reasonable excuses as to why those knives are in my toolbox. I use them to process firewood/ food lunchtimes etc. Maybe after work I'm going camping and I dint want to leave them in my back pack in my van. Or maybe I try to say they are work knives and give examples of when I use each in my work.
Depending on the police officer and what they think, anything could happen, from I've done nothing wrong or a warning or end up arrested. In this instance we will say the officer believes I have done nothing wrong.
Now although I might not like the attitude of the owner for reporting me. Can I really argue that they have not done things correctly. I really don't think so.
We could maybe say they should have voiced their concerns to me directly. But they might not have felt comfortable to do so.
We could also say that since the officer believes me they were wrong to report me. But I'd still argue that the owner was still correct, it's not their job to decide on the law.
I don't know what planet you are on, but the original OP said nothing originally about reporting him to the police, that was another numpty.
The only thing you could be reported for was carrying knives in your toolbox..........but your first few words of your fairy story, cleared you of that.........".I arrive at someone's property to do some work..." which is stated in the appropriate Law as an acceptable reason to carry a fixed blade knife..........now if you were going onto somebody's property to carry out work, the property owner would expect you to be carrying tools, but he would have no say on the type of tools you carried, so again, unless he is a numpty as well, what would he report you to the Police for?, I think as soon as he said, I had a tradesman in to do some jobs for me and he had a knife( or several knives) in his tool box, to the Police............you could probably hear them laughing as they fell off their chairs.
There are Laws, and any Law that is passed by Parliament, has to have exceptions, virtually no Law, even murder is absolute, their is always an acceptable reason to break it.