Nice to see someone else in tune with modern technology Iain, just wait till it breaks now and you loose your temper with it then throw it across the room...happens a lot!

Your Cormorant might not have been a sinensis as many carbo show just as white head etc, especially the older ones and those in the peak of full breeding pluamge like now. There are other more reliable features for identifying sinensis but they require the use of a telescope most of the time and a fair degree of appreciation of variation in betwen the two sub species.