AlanM - probably not really the place to ask but here goes anyway. Advice on what SHOULD have been pilot action in the following circumstance.
Aircraft heading south into Denham, RIS from Luton (weather poor), Luton "advised" a height until cleared to Denham Radio. All went well and overhead Denham, airfield in sight and landed safely and without fuss EXCEPT infringement of Northolt because of height. Telephone call to explain and everyone OK about it - no harm done etc and aware because of Luton squawk. Ideally descent would have been appropriate but Luton advice and high cockpit workload dictated otherwise. Not seeking to blame anyone but the pilot (his responsiblity of course) but what should have been done.