"The point of this story is sub 250g, the likes of nano drones, it is ludicrous when applying common sense to require ATC permission to fly a genuine toy drone, hence the emphasis in this example of a £15 drone."
No, I think it is all or nothing. It does not matter is its a toy, it has no business being in the air. In fact that probably applies more because it is a toy. Even toys like these go wrong, fly off and smash up the internals of a planes engine. Or they fly off and blind the poor lad down the street. The toy ones cant handle a wind so could simply be blown off. Tether them, that might do it. Otherwise put wheels on them and make them roll around the ground like radio control toys should.