The “square” formation is only to show the Toy Soldiers in a single pic. Cavalry had not use at all “inside”. But even more important the “square” as such was not used at all intensively at that time… so you will forgive the artistic licence!
In fact the purpose of this “parade” was to count them all, stop adding more troops without sense of perspective… and find where to put the two machine guns newly commisioned!
Vast majority of them are REPLICA METAL MODEL SOLDIERS (Andrew Stevenson), complemented by DORSET SOLDIERS (Antony Spencer) and even 4 Gordon Highlanders done by my friend Paul Watson in a moment of yours truly deep anguish!…
You must read Major C.E. Callwell (Royal Artillery) opus SMALL WARS (Their Principles & Practice).