OK I better update this thread on what I decided, and in the end I got the... Nikon D800E
Firstly can I thank everyone for their feedback and a big thanks An Exception who took time to email me sample photo's of stuff I was looking for.. although in the forum he may come across as favoring Nikon but in the conversations we had he was very fair to both.
Anyway i'll explain my decision.. I was lucky enough to be able to play with both Camera's and they were both really good and both offered what I considered to be an upgrade to the 5D MKII. I think in image quality the Nikon is better purely down to the extra MP's however I wasn't going to let that be the deciding factor.. the canon was better at Video however after reflection I only used that feature on the 5DII a couple of times. The AF on the Canon is apparently better but I couldn't tell however the 6FPS was definitely an advantage and the 4 FPS did concern me as that's pretty much what the 5D MKII is. I liked the feel of the 5D MKIII it sat comfortably in the hand, the D800E felt bulkier. Their were controls on both that I found awkward so they cancelled each other out.
One of my major considerations was I wanted to keep my 70-200 2.8L II or get the Nikon equivalent but I expected to loose a fortune on it and my other lens and on that basis I would have kept with Canon.
To my surprise though the Lenses keep their value very well, and there was discounts available on buying a lens with a Nikon and also cash back on them to! The shop gave me prices for my gear and I calculated the difference between buying the 5D MKIII and keeping my present lenses or changing to Nikon with equivalent lenses.. to my surprise it worked out cheaper to change to Nikon and get new lenses! it was only then I made my final decision.
I picked up the D800E, 70-200mm AF-S Nikkor f2.8G ED VR II, 24-120mm f4 G AF-S ED VR (which I wanted as a walkabout) and a 105mm f2.8 G AF-S VR IF ED macro.. I also got thrown in a Grip which apparently will address my FPS concerns.. I still need to get a couple of extra lenses but will pick them up on Friday/Saturday after I've looked into it more.
I hope I've made a good choice, I'm sure there's isn't a wrong choice and tbh I'm hoping the change will be a good thing for me and re-light the fire for photography which at the end of the day is what I wanted.. Tech sheets don't make interesting photo's so I need to get out making the camera work!
All I need to do now is learn how to use the Nikon system and try to remember Lightroom/Photoshop
I look forward to taking part in this part of the forum again !