Fiona,
Some nice shots there
I love the brooding nature of number one, for me it'd be better with a touch more detail in the statue, I don't think it's got an interesting enough profile for a sillouhette. You could try doing that with a bit of fill flash but I'm not sure that a hand held or on camera flash could light something that size evenly from that distance. You could have used a longer exposure but that would have lost the dramatic sky. You could add a curve in photoshop to tweak the darker areas of the image. I hope you don't mind but I had a go at that. Given the chance I might have moved the statue a bit to the left in the composition so he was looking into the shot but all this is personal opinion and you may not agree.
I really like two and three, the mono conversion has been done well and is very effective, two is especially is good with the different tones you managed to keep in the trees.
Four is a good idea, again I'd like to se a bit more detail in the foreground, a tiny bit of fill flash to bring out the bird's eyes perhaps?
Five's a lovely sharp shot, I'm a bit put off by the verticals in the middle section of the building but the light's really nice, especially with another one of those brooding skies over the top.
All in all, some good shots here.