Possible Clues:

• One place troops gather (2 words)
• It has the military stamp on it
• Where troops gather may be suggested by a padre?
• Place for drill clip holding plug attached to earth
• A Republican, possibly aged Republican, located in prison site of drills?
• It has many stamps on it
• Place to display artist in flat, with ecstasy in powdered form
• March at Croke Park is for The Gathering of the company men
• Drill demonstration area
• Where troops get their marching orders?