Hi Pat, my recommendation does not contravene any UK law. I think what you are referring to is that you can only carry a non-locking blade of less than three inches without reasonable cause (e.g. a non-locking penknife). That said, there it is not illegal to own a fixed blade knife or lock knife or non-locking knife of more than three inches. Any knife can be considered an offensive weapon under certain circumstances. But this is no different to, say, a chisel. Just as a carpenter can carry tools to a job and use them on a job, so can an outdoors person take suitable (and legal) tools to the woods to use them.
You’ll obviously need to tailor your survival kit to the number of people who will depend upon it. If you are going out for a solo camping trip, you won’t need as many supplies as if you are heading out with an 8-person team. The number of people depending on the kit won’t affect some of the items in the kit, but it will affect others. For example, you’ll only need one fire starter, no matter how many people are in your party. By contrast, you’ll obviously need to adjust how many space blankets are included with the kit, depending on the size of the group. My $100 Walmart Survival Kit - 7 Day Survival Challenge - The Build