B55 having had a GPWS alert at the end of a long flight, and LHR to NBO is a long flight you are tired and although you feel up to it reaction time is slower, a GPWS alert does just that and any pilot should follow procedures, on the second approach you are really awake and you brief that if the spurious GPWS comes on again you will continue that is good airmanship that is what we did the alert did not come back, what just what if it had been a light aircraft it happens. Stick to procedures they are there to help you in the times when your body most needs it. On the same or similar subject what would you do in VMC and TCAS tells you too climb, look out of the window before carrying out the action no way you pull up you dont look just do what you are trained to do. Believe me closing speeds of 1000 kts dont give you time to mess about it happens and yes that has happened to me as well, its even more scary when you look at the computer generation at the CAA, time in both of these circumstances you just don't have.
Rant over.