Unsub, you are certainly right with the comments you make in the first paragraph.
"I have an idea for a UK legal tactical folder actually" That would be interesting, under the 'Offensive Weapons Act' anything carried that is 'intended' (kitchen knife on the streets on a Saturday night), 'adapted' (sharpened steel comb) or 'made' (dagger) to cause injury is illegal; so a legal tactical folder would be a great trick! (More details please!! Not intended as a flame!)
Para 3&4 ditto good points!