Canvassing here has met with little success, although 1% seems about right. In rural Devon it really isn't a case of what you know but who you know. A good starting point are Post Office and, if you can find any, local shop cleans. Referral seems to be more effective than anything else and local advertising produces very few results.
Yell.com, Google and any other lists I've ended up on have proved to be pretty good and attracted quotes for Business premises.