Ok, so I came home tonight and decided to have a closer look at the Old LCD I replaced. I could see that there was definitely some dark blue film stuck on each side of the glass, (I thought it was more a sepia colour before). The 2 pieces of glass fused together had what I assume maybe some kind of liquid in the middle, therefore the name Liquid Crystal Display.
Bear in mind I haven't researched how liquid crystal displays are made. Anyway, I applied some heat to the Display with a heat gun and the clear spots started to disappear, however the dark blue film started to peel away from the edges of the glass. I peeled the film more (see Pics not great detail).
I cleaned the sticky stuff off the glass and I could clearly see the spots/blotches between the glass. Guess that's either the liquid drying up or something, due to temperature fluctuations and just wear and tear over time.
Thought you all might be interested.