I know that normally you have no right to park outside your own house, and have to rely on considerate neighbours. However, the street I live on is unadopted, on my deeds my boundaries are to the middle of the road. Does this make a difference and is it private property? Can I stop my very inconsiderate neighbours parking on my front?
I would have thought that if the road is within your boundary (and not subject to any kind of covenant) then you can do what you want. You might get a more reliable answer if you post the question in "Law" rather than "Motoring"
If a vehicle is parked on private property this constitutes a trespass. However, it is unlikely to be treated as an 'aggravated trespass' (a criminal offence) but rather as a 'civil trespass' in which case you may sue the perpetrator for damages in a court of law.
Earlier this year a Bill was introduced before Parliament to create an offence of Criminal Trespass with a Vehicle, which would have encompassed the situation described. Unfortunately the Bill appears to have been dropped.