Like most such "regulation" they don't seem to have given much thought for how it will be enforced. In many cases if they put the effort into education/guidance/visible presence they'd achieve much the same without troubling the council's legal team! It is a thin end of the wedge - do you want to show your insurance on demand to any official to use your dinghy tender? Do you want to stop people using foiling dinghies / windsurfs? Do you know want kayaks to only be able to launch at official slipways and prove their competency? What if the kayak has a small electric motor? They mostly use the word operate but then use the word ride for bathing zones - are those different things? There's no explicit exemption given for emergencies, not for use of PWC by emergency services (not sure if the RNLI use them, or might want to use them, on any beaches in the ares?)
Yes, I was going to say is there any formal legal definition of Personal Water Craft (PWC)? If not the whole thing is unenforceable?
There's a definition in the RCD/Recreational Craft Regulations, but generally law shouldn't assume a definition in some unrelated legislation applies to this - unless the writers of the Order specifically create the link, it says:
“personal watercraft” means a watercraft intended for sports and leisure purposes of less than 4 metres in hull length which uses a propulsion engine having a water jet pump as its primary source of propulsion and designed to be operated by a person or persons sitting, standing or kneeling on, rather than within the confines of, a hull;