Some other bits from Raggy's link:

Dubliners cheered the British troops dragging the 1 pounder gun landed from the Helga into position to fire on the rebels.

Who was it that hoisted the flag on a top to deliberately mislead and misdirect fire thereby potentially putting civilian lives at risk - Eamon DeValera wasn't it Raggy? But as your link states - No lives were lost in the Artillery dual your link describes.

The link showing Liberty Hall shows that the gun-fire from the Helga wasn't too shoddy judging by the entry holes that can be seen.

Jom, as Keith A states Firemen probably had no idea what Heavy Artillery was, remember in 1914 the British didn't have any and unless the Firemen of Dublin kept themselves abreast of the changes being wrought in the army of Great Britain then there was no reason why they would know the difference - Sort of like you and Raggy they'd be clueless.

Now tell us all what Heavy Artillery Units of the British Army were deployed in Dublin on the 24th April 1916.

You have still to demonstrate where and when you have shot me down.