I too have been driving for many years 40+ without having an accident or any points on my licence. I have good spacial awareness and can reverse perfectly without help and I use my mirrors as necessary. I still always turn round and check and shall continue to do so!!
http://www.findleys.co.uk/practical_tutorials/ reverse_to_left.html
http://www.findleys.co.uk/practical_tutorials/ reverse_to_Right.html
and taken from these links
"You need two reference points to complete this manoeuvre. You need one for the straight reverse and one to help you reverse around the corner accurately.
It has been pointed out by many pupils that by looking in the near side wing mirror they can see the kerb quite nicely and reverse accurately around the corner. While this is true enough it is not allowed in this manoeuvre. The wing mirror has a very limited zone of vision, so therefore continuous observation into it could not be seen as safe by the examiner. By using the reference points below you will be able to complete this manoeuvre by looking over your right shoulder alone"