12Watt Tim
Exactly.
In any event whatever the specific circumstances that was not the point.
If you were receiving a service of whatever colour and a squawk I'd guess even though it is not the controller's responsibility 9 times out of 10 they would deal with you well before you had Heathrow's tower in view - or any other tower of importance.
The end result is a much better outcome for all concerned - less form filing for them, less disruption for CAT, and no tea for you (in less than happy circumstances).
In fact if you infringe and are not availing yourself of a service when one was available I'd not have much symphathy for you, so you had better make sure your nav. is red hot.