The recently raised Leinster Regiment Association believed that recognition for the regiment with which O'Neill had won his Victoria Cross should be displayed on his grave. Therefore, a ceremony was held in Holy Trinity churchyard in which O'Neill's headstone was cleaned and a memorial plaque placed over his burial plot pointing out that he was serving with the 2nd Battalion, Prince of Wales' Leinster Regiment when he earned his Victoria Cross on two dates in 1918. The memorial stone was unveiled by Mrs McCaughy and her cousin Mrs Molly Hayes, both relatives of John O'Neill.

[ London Gazette, 26 December 1918 ], Moorseele, Belgium, 14 & 20 October 1918, Sergeant John O'Neill MM, 2nd Bn, Prince of Wales' Leinster Regiment.

For most conspicuous bravery and devotion to duty near Moorseele on 14th October 1918, when the advance of his company was checked by two machine guns and an enemy field battery firing over open sights. At the head of eleven men only he charged the battery, capturing four field guns, two machine guns and sixteen prisoners. Again, on the morning of the 20th October 1918, Sjt. O’Neill, with one man, rushed an enemy machine-gun position, routing about 100 enemy and causing many casualties.

Throughout the operations he displayed the most remarkable courage and powers of leadership.

John O'Neill was invested with his Victoria Cross by King George V in Buckingham Palace on the 2nd August 1919.

On the 13th February 1962, John O'Neill's Victoria Cross medal group was placed into the care of B.A. Seaby, a numismatic company, for sale in their forthcoming auction. On the same day a gang of thieves parked a van outside the motor showrooms on the ground floor of Seaby's premises. They forced the showroom door to reach another door giving access to the coin dealer's offices. The gang then carried oxy-acetylene apparatus hidden in rolls of linoleum into the building and spent the next ten hours burning open three safes.

Coins and medals valued at £30,000 were stolen, including the medals and decorations awarded to General Thomas Makdougall Brisbane, after whom the Queensland capital is named, and the WWI Victoria Cross medal group awarded to Sergeant John O'Neill, 2nd Bn, Leinster Regiment. They are valued at £2,750 and £535 respectively.

An immediate reward of £2,000 was offered by Tyler & Co, city assessors, and warnings were circulated by the International Association of Professional Numismatics to markets in Switzerland, Italy, Germany and France. To date, no sighting of John O'Neill's Victoria Cross has been made.

Medal entitlement of Lieutenant John O'Neill - 2nd Bn, Prince of Wales' Leinster Regiment

• Victoria Cross
• Military Medal ( MM )
• 1914 - 15 Star
• British War Medal ( 1914-20 )
• Victory Medal ( 1914-19 )
• King George VI Coronation Medal ( 1937 )
• Knight, Order of Leopold II ( Belgium )
• Medaille Militaire ( France )