Hey thanks! I've altered my profile to allow editing of pics.
Thanks for highlighting the depth of field issue with the bigger apertures. I really haven't even grasped the basics yet so that was a very useful tip! Point taken about the IS lens too. I'm very happy to use a tripod where necessary, but I really wouldn't want to be shackled to it. I'll have to think carefully whether the Tamron really would be the best option or whether I should just grit my teeth and go for the Canon 17-55mm f/2.8. That really does appeal, but the trouble is my eventual goal (if I can develop enough skill to justify it) is a 400mm lens for bird photography - a pricey investment! But that's a looonnnng way off! Anyway it's clear enough now that I don't need to rush into anything.
With the exposure issue in the RAW file, would spot metering have helped here?