Now the rockwork base was a simple and rapid affair.
Basically put, the main base was one of my old resin cast-offs.

The 'rocks' were a lump of breeze block to begin with,
I just took a hammer to it and had a short
bit of rock breaking action.

Once done and with a cement made from fine grit
and white PVA glue, appropriate lumps of said
breeze block and glue were liberally laid about the place.

A coat or two of semi-gloss black about the
bottom and a bit of foam paper on the
underside and that was that.