Local councils have the freedom from Parliament to to inforce and make there own rules for non criminal cases.
This is called "The Law of Tort"
For the purpose of debait Hounslow Council have made it a "Law of Tort" that cars will park in Islay Gardens TW4 5DR with 2 wheels on the kerb and 2 wheels off within the dotted lines:)
If there is no signs on the lamp posts and no dotted lineson/off the pavement, then in all probability Statute law - act of Parliament will come into force and you are not allowed to park in this way!