Many thanks to all for the positive comments. Much of this has been experimenting with materials that I'd not used before and, although I've been fairly happy with the results so far, it's great to know that others think I'm getting a few things right.
Mikkel - yes, the 'framing' of the railway was one of the intentions when I started designing this layout. After a previous attempt that was too narrow and had virtually no surrounding landscape, I wanted to ensure that there was just enough to avoid it being all railway. There will be a road along the entire front of the layout with a grass bank leading down to the tracks. The station area and beyond will have the batch (colliery spoil tip) as a background. Hopefully, these will continue the effect along the full length of the layout.
It looks like I've managed to fool you with that photo of the wagon, it really is on the rails. Mind you, I had exactly the same reaction when I first saw it. I think the illusion results from two things. Firstly the yard surface continues right up to the nearest rail so you can't actually see it, and secondly, as Tim V has spotted, the track has inside keys, so what looks like the nearest rail is actually the far side of the siding track.
As to the fencing, it's little features like this and the inside-keyed track that, once I know they were there, I won't be satisfied until I've at least tried to represent them. On that note, I've been wondering for a few weeks about whether I can live with a little error in the track. I won't say yet what it is and, if no one spots it, then maybe I'll leave it as I really don't want to have to rip the track up at this stage.
Miss P - I'm beginning to find a rather devilish satisfaction in modelling a real prototype where there are all sorts of features that one might think couldn't happen. Why they put the loading platform there I don't know, but it was like that before the 1908 changes. Even though this end of the layout it quite highly compressed, the relationship between the platform and the crossover is about right. It looks like there was just enough room for a wagon or van to have it's doors, though not its full length, alongside the platform without fouling the crossover. Why on earth would anyone design it like that?
I wondered if anyone would question the dark stone posts. There is a very clear photo of the Monkton Combe gates on p84 of Maggs & Beale, The Camerton Branch. The authors suggest 1910-ish for the date which is plausible, though it could be later. This clearly shows the posts in a mid-grey tone, lighter than a GWR wagon and much the same as the column of a gas lamp. Given the good range of tones in the photo, dark stone would appear to be the best match, but I'm open to other arguments.
Tim - it would be good to see the picture if you can find it. The only clear one I've seen dates from the early 1950s where they appear to be very dark, probably either black or dark brown.
Nick