From the Highway code:
You've caused "damage... to ... property" so you must report it to the police. I have some notion that this applies to car drivers and not to cyclists, though the section I have quoted doesn't back this up. Anyway, you are legally required to report it.
If you are involved in a collision which causes damage or injury to any other person, vehicle, animal or property, you MUST
- stop
- give your own and the vehicle owner’s name and address, and the registration number of the vehicle, to anyone having reasonable grounds for requiring them
- if you do not give your name and address at the time of the collision, report it to the police as soon as reasonably practicable, and in any case within 24 hours
You've caused "damage... to ... property" so you must report it to the police. I have some notion that this applies to car drivers and not to cyclists, though the section I have quoted doesn't back this up. Anyway, you are legally required to report it.