I use a 50mm mdf round base. With à drill, I cut off a 25mm round space wich will be used to fit a plastic base (games workshop socle).
Some figures are used to create à scene. In this exemple, the standard and à warrior holding the general's steed (Renegade miniatures. The horse is from the LOTR Games Workshop range. The saddle has been modeled with green stuff to represent a gaelic one)
A Catuvellauni general
Trisega the Durotrige, sister of King Merricus