as regards the anti vandal paint i found this
Anti-Vandal Paint and the Law
Under the Occupier's Liability Act 1984 householders owe a duty of care to anyone on their property, whether they are entitled to be there or not. The duty is to protect people from an injury as a result of a foreseen hazard. If anti-vandal paint has been applied to a wall and an intruder slips and injures himself as a result, this is something that the householder could have predicted. Householders could also be caught up by the Highways Act 1980 if anti-vandal paint is used on a wall or surface which adjoins a public highway. The Highways Act states that care must be taken to avoid "harm or injury" to any person or animal using the highway.
The local crime reduction or crime prevention police officer should be happy to advise householders if they have any doubts about the legality, or efficacy, of any intruder deterrent methods they intend to use.
Discharging the Duty of Care
To discharge the duty of care owed to trespassers, householders must put up a warning sign if they are using anti-vandal paint. The sign or signs should be placed in the area where the paint is being used. Suppliers of anti-vandal paint usually also sell warning signs. In addition the paint should only be applied to surfaces above two metres high so that innocent passers-by do not come into contact with it.