Thanks everyone. I wish I could paint this image but that's well beyond anything I can do so it's strictly photo montages for me.
As to the moon, when the reflection is on the water it's a mirror image so reversed, but the viewer sees it from above not below so would the crescent shape point up toward the mist, the far distance, or would the tips of the crescent point in the direction of the foreground? I should know which way round this goes but my brain refuses to except either view as right.
I'm going to try to blend the cat in a bit better, as it does still look as if it's pasted on, and add a small group of fireflies as suggested. I've got an idea to copy a section of the background, lay it around the edge of the cat and fence and then experiment to see if the background colours help to settle the cat more into the image. Going to have a look at doing some work on the clouds too. I didn't make the background so making changes to that might involve painting, not my strong point.

The reflection of the moon should be a straightforward vertical flip.

What about something like this, then ripple the water where the moon is a bit so you can just see parts of the moon. You could always add a bit more brightness to the lower part of the moon to give more light too.

caz: i love this!! you're doing a great job on the atmosphere, the composition is really good and i think the fireflies will make a nice addition too . about making the cat blend in better: photo comix has a trick that i know he's posted here on gc a while ago - couldn't find the thread right now, but i know it's here in the tips and tricks or tutorials sections. he makes a duplicate of the background layer, places it over the render layer (the cat in this case) and puts it on overlay. i've used this technique a lot since he tipped us off about it and it really helps making the renders blend in. i often tweak the overlay layer using a layer mask so the effect gets stronger on the render than around it and i smudge the layer over the render so i don't get sharp details of, say, tree branches over the render. another way is to just pick some colours from the background layer, paint them on a new layer over the render and put that on overlay.

Thanks for the tips and comments, guys.
I tried the overlay trick as suggested by AnMal and yeah it does make the images blend together better, it did tend to make the overall image darker though. So what I've done is to alpha to selection the cat layer, grow the selection by about 8 pixels and make a copy of the background layer. I then shrank the selection by 16 pixels and deleted the centre of the new background layer so that there was just an image 16 pixels wide that fitted around and over the edge of the cat. Gaussian blurred this a couple of times, about 30 pixels each time, and that seems to have settled the cat more into the background image. I also set the mode to overlay and dropped the opacity down to 30. Still got some more work to do on this but once it's done I'll post an updated version.

Here's the latest incarnation of this image. I think it's pretty much done now but as always I'm curious as to what others think, and if any improvements are needed.

That looks great!

Wow that's very good Caz, I love the palette and the detail is engaging.

caz: you've done a great job on that! it looks a lot more like a unified whole now and the moon reflection is looking just right. a beautiful and very atmospheric composition.

Beautifully done Caz.

Thanks for the comments everyone. I really appreciate them. This image is going to be a Christmas present for a relation of mine. I really like it that I can now make presents instead of giving out gift tokens, it's more in the spirit of the time of year for me.

woo hoo, couldn't be better, KUDO's

Thanks, Molly.