It seems that there is no right of appeal if warned under this act and no chance to defend yourself. The police only need to have reasonable grounds for believing that an offence has occurred … in my case a complaint by a householder that I have sounded my horn. This has been done when passing a car parked on the outside of a left hand bend opposite a high brick wall which blocks my vision of oncoming traffic when I am travelling along the inside of the bend – see this post for details. It seems that this Act can be open to misuse and used to intimidate others in collusion with the police.
Taken some advice and it has been suggested that I contact:
Highways and Road Safety at the local council – done
PLUS – get the police to put in writing that I have been asked not to sound my horn when approaching a perceived hazard. If I do have an accident then send a copy of the letter to my insurance company along with the claim!!!
Also … if I DO have an accident – Heaven forbid! – I can look at negligence and public highway nuisance legislation aginst the owner/driver of the parked car as they arenow aware of the danger posed to other road users if they continue to park there.
59 Vehicles used in manner causing alarm, distress or annoyance
(1 )Where a constable in uniform has reasonable grounds for believing that a motor vehicle is being used on any occasion in a manner which—
(a) contravenes section 3 or 34 of the Road Traffic Act 1988 (c. 52) (careless and inconsiderate driving and prohibition of off-road driving), and
(b) is causing, or is likely to cause, alarm, distress or annoyance to members of the public,he shall have the powers set out in subsection (3).
(2) A constable in uniform shall also have the powers set out in subsection (3) where he has reasonable grounds for believing that a motor vehicle has been used on any occasion in a manner falling within subsection (1).
(3) Those powers are—
(a) power, if the motor vehicle is moving, to order the person driving it to stop the vehicle;
(b) power to seize and remove the motor vehicle;
(c) power, for the purposes of exercising a power falling within paragraph (a) or (b), to enter any premises on which he has reasonable grounds for believing the motor vehicle to be;
(d) power to use reasonable force, if necessary, in the exercise of any power conferred by any of paragraphs to (a) to (c).
(4) A constable shall not seize a motor vehicle in the exercise of the powers conferred on him by this section unless—(a)he has warned the person appearing to him to be the person whose use falls within subsection (1) that he will seize it, if that use continues or is repeated; and(b)it appears to him that the use has continued or been repeated after the the warning.
The explanatory notes for this section are as follows: http://www.legislation.gov.uk/ukpga/2002/30/notes/division/4/1/16/11
Section 59: Vehicles used in a manner causing alarm, distress or annoyance
326.This section gives the police new powers to deal with the anti-social use of motor vehicles on public roads or off-road. It includes (under subsections (1) and (3)) powers to stop and to seize and to remove motor vehicles where they are being driven off-road contrary to section 34 of the Road Traffic Act 1988 or on the public road or other public place without due care and attention or reasonable consideration for other road users, contrary to section 3 of the 1988 Act (as substituted by section 2 of the Road Traffic Act 1991). By virtue of subsection (8), these new police powers will not be exercisable until regulations under section 60 of this Act are in force.
327.Subsections (3) and (7) provide that an officer may enter premises, other than a private dwelling house, for the purpose of exercising these powers.
328.Under subsection (6), it is an offence for a person to fail to stop a vehicle when required to do so by a police officer acting in accordance with this section. The offence is punishable, on summary conviction, to a fine not exceeding level 3 on the standard scale (currently £1000).
329.Subsection (4) requires the officer to warn the person before seizing the vehicle, to enable its anti-social use to be stopped. By virtue of subsection (5), the requirement to give prior warning does not apply where it is impracticable to do so or where a warning has previously been given.
Immobilisation of Vehicles
Dr Huppert: To ask the Secretary of State for the Home Department if she will assess the merits of introducing legislative proposals for a right of appeal against seizure and removal of vehicles under Section 59 of the Police Reform Act 2002. 
James Brokenshire [holding answer 18 October 2010]: We have no plans to introduce such a right. Section 59 enables the police to seize a vehicle they reasonably believe is being driven both carelessly or inconsiderately on-road or off-road without authority and in a way that causes or is likely to cause alarm, distress or annoyance. This power of seizure can only be used in carefully restricted circumstances and following a warning. A vehicle that has been seized must be released immediately on payment of a prescribed sum intended only to cover police costs and this payment is waived if the owner is not personally at fault. When introducing the legislation the then Minister formally declared it compatible with the provisions of the Human Rights Act 1988.
The remedy for any person who wishes to challenge the police’s decision to seize their vehicle is an action in the county court for trespass to goods. It is also open to them, if they believe the police acted in any way improperly, to make a formal complaint against the police.