Don't believe there is I've never been able to find anything set in stone other than on a forum many years ago where a poster purporting to have been a serving police officer said even he wasn't aware of any specific laws surrounding it. The only advice was to take notice of signs in any public spaces which might stipulate no RC vehicles allowed but, so far I've only ever come across a couple which said no RC boats or aircraft. Think as long as you're not being a nuisance in which case the police could ask you to move on then should be fine as long as you're careful and respectful of others in the vicinity. Most of my running is at a couple of local grass bike tracks, so I'm just careful if people on bikes or kids are nearby especially when I'm running 6S and dogs, if the dog gets close I will stop for a while until they move on. So far had dog walkers/others perfectly fine, some take an interest which is nice.