Re: Busybodies entitled to see your ID card?
"If the law specifically requires citizens to identify themselves to the authorities on demand with an official photograph document, such as an ID card or a driving licence, as is quite common here in continental Europe, then you've got to comply."
I've lived in various European countries in my lifetime, UK, EU and non-EU. Whatever the law actually says, in practice it is very rare to be asked for ID by the police in Europe (outside of traffic stops), and I've never been stopped and asked for ID in 40+ years in any European country. (Of course YMMV depending on what areas / people you frequent and/or your skin colour)
In the case of traffic stops, being asked for a driving license is to establish whether you are allowed to drive a vehicle rather than to establish your identity - and this is the same in UK as everywhere else in Europe.