One of those pilots was a student on a QXC from Thruxton to Sywell. His heading was supposed to be 027 degrees for 72 miles. Unfortunately he ended up flying 072 degrees which put him in the Heathrow Zone. I believe that he mistook the Madejski Stadium at Reading for the Oxford United ground and RAF Northolt for Kidlington.
It is very easy when under a little bit of pressure to convince yourself that you are where you should be rather than where you actually are. A few other issues compounded the problem but he did eventually get onto 121.5 when he realised his error.