So after Modeling the hands and feet i moved on to the head. I came across several problems whilst doing this. The book i was using as reference modeled the head and body within the EP curve we made at the start. But as I made my gorilla quite stocky and muscular I couldn't really do this as he doesn't really have much of a neck.
So i Decided to block it. The main problem that occurred during this process was moulding the vertices to fit a basic muscle structure for a face, from a bulging neck which it was before. The whole process was very time consuming. I then had to Extrude eyebrows for him and pull back basic eye sockets and a mouth for Cornelius.
Finally I notices that there was a hole at the very top of cornelius' mesh. Which after scouring the internet for hours I found I could bridge the vertices for so yet another problem solved.
Overall i'm pleased with the low poly head. The next step is to mirror the geometry.