How do I talk about methodology mistakes In a scientific project report?
You wrote:


  I want to include it as a chapter in my report to show the marker that I have put over the recommended 300 hours work into my project


Nooooooooo.

Don't do that. This is a postgraduate degree, and you're expected to take the research seriously. It's not a 9-5 grunt job or prison sentence where you turn up, serve your time, and get the reward at the end of your allotted time.

Show what you've learnt. That's what the markers are interested in. You say that you've learnt the inner workings of neural networks. That's great. So demonstrate and document what you've learnt.

And don't document the tortuous process you used. Don't describe how you went from A to B via C,D,E,...X,Y.

Just report that you started at A, ended at B, you've found that the shortest route between those points is {whatever it is}, and briefly document the dead ends and traps that future researchers should avoid.