I think this is something that you need to address sooner rather than later! For example, what was it that got you into setting up an online directory listing? Did you think it was just a great idea, or had you noticed other people doing something similar? If the latter then you have somewhere to begin. If the former, then I really do expect that your ‘great idea’ will have competitors somewhere – simply because it’s great!

Without knowing more about your specific site, I can only offer broad ideas. For example, the UK site you mention, you could do a Google search to see who links up to that site, using the link:http://www.school-workshops.com/ parameter. If you can also use Google’s advanced features to zero in on Canadian-only sites (which I’m not sure about, being in the UK myself) then you’d have a better chance of finding someone.

Don’t be restricted just to immediate competitors either. There may be other services for education that provide something similar or, having seen what you do, might decide to muscle in on what you do. So these could be local universities, colleges, adult education services, or even public services such as libraries.

If this doesn’t give any results, try talking to people! As you’re out pitching for business, ask people if they know of any other similar services. They’re your experts out there, so use them.

Hope this helps, and good luck!