EuCampaign122Speeches
The corbynfacts website originally claimed that Corbyn "gave 122 speeches during the course of the [EU] campaign".
This was a misunderstanding of the Loughborough University "Media coverage of the EU Referendum (report 5)" and so wasn't even close to being accurate - the report listed media appearances (so a clip that played on 4 news outlets would be counted 4 times, for instance).
It's now changed to list exactly what Corbyn did over the course of the EU campaign.
An analysis of this is here: Here, There And Everywhere
In terms of rallies, we're talking about a dozen, and 5 thousand attendees altogether at the most. If you compare to the effort and audiences being mustered for Corbyn's leadership defence campaign, you may get an idea of why many feel that Corbyn wasn't exactly pulling out all the stops on the EU front.