Jennifer, you are right - the reflections of the clouds are a problem so I have put the clouds back in the sky. My initial scan was a problem (as usual - my scanner tends to add extra grain into the clouds when using color negative film) so I tried removing the clouds - but, other than the reflections, the image looked too sterile. So, the clouds are back after a re-scan of the negative using the built-in grain removal software of my Nikon scanner (rather than Neat Image afterwards) with, hopefully, better results in the sky.