The police came to my house with a specific search warrant (misuse of drugs act 1981). It had no name of the occupier, just the house number and car rego. They searched the premises and vehicle for drugs and found nothing with respect to the warrant issued. they did, however, find an old disused triggerless crossbow. They said it is a prohibited weapon, and took it away. They also said they will be in touch and that I may be charged with an offence. Can they do that under Criminal Law (considering it was a warrant for drugs, not weapons) and if so, how long will it be before they charge me?