Properly used, GPS will certainly reduce the chance of getting 'lost', I agree. But it's still vulnerable to 'Gi-Go' if used incorrectly.
As a minimum, I personally like a line on a paper map as well even when using a GPS route.
If you DO become lost, admit it. Then seek help. All the old 'percentage of distance flown since last position fix' stuff was fine in the days of few airways and Tiger Moths without wireless, but will probably be a waste of time nowadays and you'd inevitably end up somewhere uninvited! Far better to tell whoever you're talking to (if they have radar); if not then the nice chaps at D&D will help to keep you out of the smelly stuff. A low time, relatively inexperienced pilot uncertain of his/her position in the south east UK probably does merit an 'urgency' call, I would suggest.