Hoople - 6:30 pm on Jan 14, 2013 (gmt 0)
US experience here from 2009:
My one non profit customer had another non profit 'competitor' doing meta-description SPAM listing on their website listing the organizations name and town. Both are BnM single location orgs separated by 100 miles. SPAM showed to customers using Yahoo! and any of their search data partners.
Email takedown notice was sent and a few emails went back and forth with them in denial. Pushed a bit harder and they postured and threatened involving their transportation lawyer (1-2 more zeros in the fee than a neighbourhood lawyer).
I responded that this situation was a good candidate for a trademark case, listed a few url's of similar wins and mentioned that they would need a trademark lawyer which was more expensive (1-2 more zeros in the fee) than their transportation lawyer. The takedown occurred in 1-2 days.
A point to use later in the dialogue with them is if their board has insurance is that any judgement payout (by insurance) exposes the board to civil suit if negligence/gross incompetence can be proved. The 'proof' could be as simple as not honouring the takedown and allowing the courts to become involved. This puts their residences, savings and even funds set aside for children's schooling on the table.
I'm not a lawyer in Canada which may be different but you could find some/all of the above useful for letter writing as you are being guided by your lawyer.