Now that's a great set up.
I have my own W-Britains Zulu wars dio set up on a similar round base and highly recommend using one, as they are so versatile.
My base is an old wooden Chinese checkers board, which I turned over and covered in static grass from Woodland scenics.
I believe most craft and hardware stores now stock round craft bases of various sizes which makes it a lot easier to get hold of.
They do take up a bit extra room in a display cabinet, however I enjoy rotating mine at regular intervals.