Even your own link says says that the first squadron (No. 611) received them in August 1940. Then there are excerpts from the Operational Record Book of No. 611 Squadron which confirm the first operational use in August 1940.
http://www.spitfireperformance.com/no611-orb.jpg
But obviously your claim switched from "service introduction" to "significant use". There was significant use in one squadron. Significant use in whole Fighter Command is of course a different story.