Ahhh! if you want to be able to sell it as a 'toy' it has to carry a CE mark... See
https://en.wikipedia.org/wiki/CE_marking
Not at all sure about models etc. I would guess that it will need to be classified as an adult only product and age restricted to not have to carry the CE mark.
Chinese print CE marks on everything they produce, doesn't mean it complies with any CE certification.
As for registering, it'll be similar to the American system, pilot takes online exam and registers and places registration number onto model. This has so many holes in for exploitation and abuse a Swiss cheese would be jealous, nothing to stop you registering in someone elses name or putting a fake registration number on something mocked up on the PC, I doubt PC Incompetent will even know what to do with the registration cards to verify they are legitimate other than to look at it, since this is all going to be done electronically and all.
When my neighbour got busted for driving without a seatbelt, she did the online course and exam to avoid the points, but she didn't have a PC or internet connection, so used my laptop, utterly pointless exam when she could just open up a second tab and Google the answer or ask another person in the room for help.
But but this will ensure pilots know the rules and don't fly near airports. I can see some smart kid being busted for taking the exam 549 times from the same IP and charging a pound a time eventually lol