On cases similar to this, where there is a perception of authority overstepping their legal rights, it is best to contact the BC Ombudsman (now person) and start a formal complaint. Have evidence, speak factual, and it is their job to investigate. Having the police recommending particular shops (in this case the dealer) seems to be a bit of a conflict of interest for starters; it could just as easy be their friends' shops they dictate.
http://bcombudsperson.ca/driving-and-transportation