May I add some input as a retired Heathrow controller with over 30 years experience of watching this sort of thing happen a good many times? Infringements of the London Control Zone, even by experienced pilots, are not rare and are invariably down to poor airmanship and poor navigation.
When you first realised you were close to Heathrow and suddenly yanked the aircraft round to get away from the airport... did you not think of immediately contacting Heathrow SVFR to let them know what was happening? You were lost so it would have been very good airmanship to make contact with the controlling authority of the zone you were infringing: It would have given Heathrow ATC at least half a chance to avoid major delays at the airport because they could have vectored you straight to WW and they would have known your altitude, probably the most important piece of information you could have given them.
In Class A airspace, when it is believed that an aircraft is lost, has experienced radio failure or is making an unauthorised penetration of the airspace ATC is bound to keep other traffic clear of it. It's always difficult to guess the intentions of the lost pilot but a sudden and dramatic change of direction, with no information on altitude, would not have made life easy for those trying to keep commercial traffic safe.
Please remember that controllers will not "book" you unless it is really necessary. Report writing and subsequent interviews take up time which could be better spent. Many of them hold flying licences up to ATPL; some fly as commanders on passenger aircraft, others are flying instructors so they are sympathetic towards those who have made a genuine error..
If you wander into a busy control zone and do not talk to anyone, ATC will endeavour to trace you. If they are successful you may be asked to telephone them and explain what happened. DON'T argue - radar does not lie! If you have made a mistake, admit it. If the infringement was minor you'll probably just be reminded to improve your navigation in future.
If your infringement causes havoc, ATC has no choice but to file a report, which may lead to prosecution.
Lastly, do pilots make use of Google Earth during flight planning? White Waltham shows up quite well and it is possible to view an approach to the 'field from various directions, angles and altitudes. As I write, I have GE showing me the view looking northeast to WW at about 1500 ft altitude. The airfield is plain to see, as are surrounding roads and other landmarks. Give it a whirl... You could even print the picture and take it with you.
I hope this helps....