Exactly. The Highway Code is clear on this, and the OP was almost certainly taught to turn round and look, and he would had to do so to pass his test. (Unless of course some physical condition prevented it.)
At some stage he would also been taught never to assume anything, especially that other road users would follow the rules.
The OP is grateful for your view will inform the insurance they are at fault.
Cannot stress how little reaction time the other driver gave me by entering illegally from the no entry part of the parking way and how this is the first time I had an incident of any kind since I got my driver's licence 17+ years ago.
But as you say.... I was clearly taught at some point to look and I should have looked. But then again , even if I had looked I wouldn't have seen the other car because of the geography of the place, which is why I guess the gym marked that way as a non entry way.
But hey... if I am at fault, I am at fault.