It's ok, I worked it out, so I thought I'd post the resolution incase anyone else was wondering.
Take the keyboard off the front (pop a credit card or something into one of the sides, then where you can actually see it pinned along the top, gently press with a screwdriver and it will pop it free) and unpin the keyboard, then there is literally an eject button located on the right hand side that pops the back panel off, the RAM is located there. Pull the 2 pins apart and it pops out. Just upgraded to 2GB 6400 and I can honestly say, there's definitely a big difference.