I feel this would be a lot quicker, but remembering the list seems quite daunting as I printed off Chris' list (but I will probably adapt and change a lot of the words) and there are pages and pages of stuff.
Can anyone say if they think I should carry on this way or can anyone suggest an easier way to remember the list of letters?
Yes, it is daunting. It took me about a month. I created a Word document, and started by pasting Chris's list into it. Then I went through one starting letter at a time and changed the words until they worked well for me. As I finished a letter, I started reciting the list as far as I knew it when driving to and from work, over and over again. By the time I finished editing the word list (I kept about 1/4 of Chris's images, and replaced the other 3/4 of the list), I had almost all of it memorized.
My average 4x4x4 BLD solve improved from 20 minutes to 15 minutes during this process. So it was definitely worth it to me. It is true that for me,
one of the nicest benefits was that I didn't have the same images coming up over and over again.
So it's certainly not the only way to go (Tim Habermaas does better than me with your current method), but I can say that it was worth it to me.