Agreed.
Yell is a dying breed of business. I found by far the best way to advertise is Google Adwords; word of mouth; and direct contact either through leflet drops or canvassing. I also found that if you are on a job and you dont clean the neighbours house yet, just popping by with a friendly smile and a handshake to introduce yourself as nexts doors window cleaner and ask them if they would like to go onto the round as well? That works very well and i have started doing that.
Steer clear of Checkatrade type websites, unless you want to be wallowing in the mire of constant price matching you end up doing the work for less profit and become less interested in providing a good service. Quite a few of my recent customer acquisitions had prev window cleaners just not bother to turn up anymore and they were found on checkatrade.