Anyway, I've had a bit of a mare. The scape slipped over sideways; I knocked it whilst I was attaching moss to some of the branches. I thought it was really stable but obviously I was wrong
It was nigh on impossible to correct with all the sand in the tank and then the polystyrene base snapped in two, so I've had to take everything out and start again. And I knocked several little roots off in the process
I've glued it back together and this time I've used even more silicon. It really is more like model making than scaping, especially at the moment. For now I've wrapped the moss in clingfilm. I'll reset and plant up over the next few days