I found that Sculptamold is often recommended as a sculpting material for scenery. Today I popped down to the local art and craft shop and picked up a bag. Its basically very fine & fuffy paper fibres impregnated with plaster. Its light but very strong, and sandable, and like paper mache to use.
So I used this stuff to start building up the sides of the pitch, embedding the odd rock, and to finish off the pitch surface.
I also carried on working on the stream, again using the Sculptamold to build up the banks, adding detail like this fallen tree (which also serves as the line for one of the wide zones).
The dugouts are in progress too now. They are lined with logs. I’ve been the neighbourhood crazy person today walking the streets looking for suitable twigs!
The twigs are attached with tile grout and then liberally sealed with PVA.