Here in the US "The reasonable expectation of privacy" controls whether you can photograph or not. For example if you were sunbathing in the nude by your pool, with an enclosed privacy fence you would have a "reasonable expectation of privacy" from anyone on the street. If you were doing so in your front yard with no fence then you wouldn't. Even in an enclosed area, you would not have an expectation of privacy from any view from the air.
While malls are considered private property, they can also be public spaces, and as private property the owners can enforce reasonable rules that on there property, including the restriction of photography if they claim its a disruption to commerce. However it generally requires that notices be placed in a conspicuous location to be enforceable. As to sidewalk, roadways, if they are public domain they have no authority to enforce privacy rights.
I have no knowledge on the UK, I've read that their rules are similar, but I've also read there are some variances.