This was my first flight to Earls Colne airfield and unfortunately I met what appears to be a student pilot on his solo navigation exercise flying the wrong way across the overhead. (Overhead joins were south-to-north that day and he flew through the overhead north-to-south). Scary.
Update June 2017: The Airprox Board's report is here:
www.airproxboard.org.uk/uploadedFiles/Content/Standard_content/Airprox_report_files/2016/New_assessed_reports/Airprox%20Report%202016265.pdf
(Their informal mandate insists that they attach no blame to pilots in order to continue to encourage reports from pilots involved in any near misses.)