SSAO Screen Space Ambient Occlusion

I isolated the inherited SSAO contribution to the overall post processing effects and was a little underwhelmed:

Definitely some AO contribution but this type of post processing is quite expensive to compute, so thought it could get a lot better.

After a trawl of what others had achieved, a refactor of the shader produced this (based on the cry engine approach):

This I thought added a lot more, but perhaps too much on the flat surfaces, so polarised to this: