I've spent a few days trying to catch up with research in a new direction. I've watched videos on tactical vests, and had an informal chat with my good friend Ruaridh Wedgwood, who is a Captain in The Army. He's also a Crossfit coach, so the crossover there is delightful! He likes the idea of the carrying vest for a festival, him and I have been to T in the Park together and know how problematic the issue of carrying things there are.
In the discussion of vests, the tactical vest is a load bearing protective carrying system, typically for things you would need on an Army expedition. It's a modular system, so can be modified to suit the needs of the wearer. It has lots of attachable pouches for different needs, a lot of them for carrying ballistics, that are attached by strong velcro to a row of sewn on fabric belts or similar. Ot the pockets are already sewn on.
As exciting as it would be to create a modular system, with my serious time constraints, I'm looking at simplicity. After learning of the Minimum Viable Product from the Gurus, I'm also aware that it's probably best for manufacture that it begins simple... especially if I'm making it! I have a little sewing experience from my textile days but nothing fancy!