Thank you so much for taking the time to respond to my question about a spike in direct traffic. My client does not do a newsletter, but he did a Facebook post and a "boost" ad. On that day of direct traffic spike he also had a huge number of visits from Facebook.Does your client send a newsletter? Often I find the newsletter software is not connected to Google Analytics and therefore comes in as direct.
Alternatively you could look at cities from which direct traffic is coming and see if they appear relevant. Entry pages?