This question got me curious, so I did a little digging. A quick check of the internet turned up the following:

http://www.shipsnostalgia.com/guides/Passenger_Ship_Disasters_-_Part_7
There doesn’t appear to be an Italian passenger liner sunk during WW2 by the name of “Italia”, though there was an “Italia” line which included the liners “Rex” and “Conte di Savoia”. However, these two ships were sunk in September 1944 (see below).

Until Italy announced itself as Germany’s allies, the Rex and the Conte di Savoia sailed as neutral ships across the Atlantic. But when the alliance was made official, the Italians put their great liners in Italian ports to prevent any sort of destruction. Despite keeping the ships out of international waters, the beautiful Conte di Savoia met a tragic and too early end in September 1943, when American bombers sunk her. In 1944, the Germans intended to blockade the harbour at Trieste. To prevent entering and exiting of the harbour they had chosen a massive object – the Rex. The Rex had to be immovable, and therefore she was decided to be sunk in the harbour entrance. The British of course wanted to stop this blockade, and sent out bombers to sink the Rex before she arrived to the spot. The British bombers arrived in time before the Germans, and completed their sad task. One of the British pilots remembers: ‘She still looked big and beautiful actually, and it seemed sad that one had to sink something of that sort. But at the same time this was war, the war had been going on for five years. And during the war you can’t really question the target and say that ship is too beautiful to sink… and so if we were told to sink it, then we would do our best to sink it.’
http://www.thegreatoceanliners.com/index2.html (REX)

On September 8, 1944, she (the Rex) was attacked by 12 Royal Air Force Beaufighters of 272 Squadron at Capodistria Bay south of Trieste. She was left listing and on-fire after being struck by 59 rockets and numerous cannon-shells. A second attack, later that day, by 12 more Beaufighters of RAF 39 Squadron and South African Air Force 16 Squadron resulted in her turning over and sinking in shallow water.
http://en.wikipedia.org/wiki/SS_Rex

However, in July 1944, the two Italian liners Duillio and Giulio Cesare were sunk in Triest.

In 1942, during the Second World War, SS Duilio was briefly chartered to the International Red Cross for a time before being laid-up at the port of Trieste as well as Giulio Cesare in 1943. The SS Duilio was sunk there on July 10, 1944 along with the Giulio Cesare, she was attacked by Allied aircraft. Her wreckage was refloated and scrapped in 1948.
http://en.wikipedia.org/wiki/SS_Duilio, and also referenced in http://www.wrecksite.eu/wreck.aspx?138966 and http://www.wrecksite.eu/wreck.aspx?139020

The only reference I have for rocket-Typhoons sinking a passenger liner was the “CAP ARCONA” in 1945, but in Northern Europe, not Mediterranean waters.

Tragedy struck a few days later, on May 3rd 1945. British Typhoon-class bombers made a raid over the area and spotted the Cap Arcona in the waters outside the city of Neustadt. Not knowing her cargo of concentration camp prisoners, the pilots could not resist the perfect target sitting dead in the water. The bombs were soon falling on the Cap Arcona, turning the one-time luxury liner into a floating hell. Smoke filled the passageways and the ship quickly took on a dangerous list. Many of the ship’s occupants somehow made it out on the top decks, but this did by no means guarantee safety. The bombs kept coming, and it would be impossible to survive for long in the cold waters surrounding the vessel.
http://www.thegreatoceanliners.com/index2.html (CAP ARCONA)

I wonder which actual ship was sunk in the attack reported? If it was a rocket attack, then I’m guessing the possible attackers were Beaufighters (RAF or SAAF), P-47’s (French or USAAF – but usually operating from Corsica, so not sure if they would attack shipping targets on the Italian east coast) or maybe RAF or Yugoslav Hurricane Mk IV’s.

Does anyone know what happened to the three Typhoons after the trials finished in 451 Squadron?

Regards,
…geoff