Update:
All sorted now, I removed the other panel on the case and the 2 x power leads were folded and tucked up out the way behind it. I have installed the card, connected the power, downloaded the drivers and it is working a treat. I have only had a quick play with the settings in Train Simulator however my frame rates have gone from 24ps to 49ps which is more than double.
I suspect I can improve on these numbers even more once I upgrade the CPU and add a bit more RAM so all looking good.
Many thanks for all your help and advice guys, as always very much appreciated.