Thanks Eve. I took a shot and could tell that the dark areas were all pure black by looking a the preview and histogram, the built in histogram is a life saver for when I am in doubt. I could see there was a lot of pure black in the photograph so did a bracket exposure of -2,0,+2 and managed to pull in much more details in the dark areas when I created the hdr image. To be honest most of my photographs outside usually don't require hdr at all, just the odd one or two like this one.
I personally try to use it sparingly, only when I really need to. I am not to keen on the "hdr" effect that some people aim for and only use it for technical purposes rather than trying to get a "hdr" look to the image. To be honest you couldn't really tell looking at my hdr photographs that they are hdr, which is the way I like it.