Just to clarify my earlier comment, I'm in favour of the use of GPS in GA. I love gadgets and I want one.
I just think the PPL is such a wonderful mixture of new knowledge, new sensations, new motor skills, the fear/exhilaration of that first solo, the skill test that it should be kept simple.
Put it this way, once you've learned to navigate by a chart you will not have a problem teaching yourself to use a GPS, just as once you know how to fly a C152 you can probably learn to fly most prop aircraft.
Anyway, this thread was about CTR infringements and I maintain my view that a pilot flying VFR should be able to avoid Heathrow's CTR without needing a GPS!