MH 152
I'm not perfect and people make mistakes, so I hope the poor chap/chapette is not too dispirited and treats it as part of the learning process. At least nothing bad happened!
at least ten departures stopped; same number broken off; stacks held up. Thousands of passengers inconvenienced and 747's 777's etc forced into manoeuvres at low level possibly after long haul flights. The consequences of CTR infringements at major airports are great.
...I do agree with your point that GPS should not be part of PPL, GPS should always be x-referenced and not trusted as sole nav aid.
Best bet when flying in vicinity of Heathrow is calling units for listening watch/FIS, London FIS, SVFR, Thames radar, Farnbro, Southend. They may not prevent infringement but if it occurs, you'll be wearing a squawk that helps get a message to you to stop the infringement early. If unsure of position call emergency fixer service 121.5, that's what they are there for.