Lovely shot and composition but I think the photo is underexposed a bit. Have you tried exposure bracketing? I find that digital late evening / sunset photos generally look their best given slightly more exposure and then corrected in lightroom / aperture – this way you get more shadow detail and colors can be picked up as well. but what do I know still shooting film :)
It’s very good Siobhan but I am a bit confused looking at it – the sun is setting in the rear of the image yet this side of the boulders are very well lit up – my mind keeps trying to resolve the contradiction … (mind you, it does that a lot without looking at images on PI).