The Commander of C Coy, 4th Battalion, was Gerry Byrne. He had been detailed to mount a 2 man patrol from St Leonards Corner to Rialto, and to fire warning shots if a British patrol came their way.
Leonard's corner is the junction between the South Circular Road and Clanbrassil St. Rialto is to the west of the junction and about where the old extension to the canal was located.
Seems an odd sort of patrol to be mounting as there were no raids that I can find near their route