Hopefully that clears up dropped kerbs for you? Seems clear as mud to Mr Mustard so he suggests the following:
Outside a CPZ - only park across your own dropped kerb or that of a friend or family member with permission.
Inside a CPZ - only park across your own dropped kerb or that of a friend or family member with permission when the CPZ is not in operation.
Near a junction is likely to be for pedestrians to cross, there might be dimpled paving, so avoid those like the plague; you will get no sympathy from a PATAS adjudicator.
Sometimes traffic wardens "forget" that they are not meant to ticket for dropped kerbs outside of CPZs (and outside of CPZ hours inside CPZs) and issue a PCN. You could print out a pdf of this blog post to give to the council as justification for cancelling their own PCN issued outside of their own policy.