Clearly you didn't read the newspaper article you highlighted, nowhere do they say the fines to the two breachers were rescinded due to illegality on behalf of the police, in fact it reiterates the rules under which they will fine breaches.
Fairly clear to me.
By the way, it was not a newspaper article it was the force's own webpage. To be honest, if you can't tell the difference between a newspaper article and the forces own webpage that links to guidance from the NPCC (National Police Chiefs Council) then no wonder you get confused.
"UK Government guidance strongly requests that people do not leave their local area. However, the Covid Regulations which officers enforce and which enables them to issue FPNs for breaches, do not restrict the distance traveled for exercise".
We have had this argument before on here and some people don't get that guidance is not regulation (law).
I am not saying it should be a "free for all" but I for one find it very worrying when the police start to decide what is legal and what isn't.
I am comfortable in what I have written is correct, perhaps you could find the actual regulation (not guidance) that states traveling any distance is not legal?
Think about it, to legally prosecute someone for traveling "too far" that distance would need to be defined in law. (it is not) The guidance talks about avoid traveling outside "the part of the city where you live". to legally prosecute someone for that it would need to be defined.
If you cant travel outside your local area why are buses and trains still running? (with no checks on why people are traveling) why were National Trust gardens allowed to stay open?
I am talking of England as I am aware other parts of the UK have different regulations in relation to this.