Lookin' good! I'm really diggin' the sandbags. I made some up myself the other day and they look...less impressive. Not that I am unhappy with my results, but yours are mint! I also really dig the large building with double balconies. GW has some decent scenery kits for sure.
Cheers for your comments. As you can see, my grey sandbags were less good as the mix was too soft - it took a lot of failed bags to get it right so I appreciate your pain.
I found a firmer mix was easier to work with, held its shape better and gave a better end result. My process was to roll the greenstuff it into a sausage and then cut it into smaller bits which were shaped by hand and then assembled. I did the crease/fold when they were part-set to minimise deformities and make them conform to the natural shape of the wall. I also took some nics out of the wall to make it look like bullet holes/battle damage rather than the drill technique. If you have ever worked with or seen sandbags the sand will always drain with gravity, leaving an even distribution rather than a perfect hole. This video was the inspiration for my process: https://www.youtube.com/watch?v=hWCG1SOJxOo