try websites like
http://www.thinkbroadband.com
http://www.ofcom.org.uk/
they should give you the known stats and then stick up a poll on a thread here and get as many as you can to say how many they have. In your report explain that you used figures from "wherever" and tested those figures with your own market research and they confirmed the given figures by whoever.
That just shows you haven't just googled or stood in a street, you have used your noggin and tested known data.
Well that's what I would do anyway