This might be of limited appeal, but some excellent pricing that hasn't been seen in a while from one of the the majors in Business Class from Melbourne (also from Sydney but at around $6200).
Check for dates via Google Flights and book direct with Etihad. These are available in each month up until June 15th.
Book your seats by 18 January for travel between 23 January - 15 June 2024
Sample Dates- Melbourne- Rome May 17th-31st $5974
Pretty sure you could save a few hundred by booking Singapore-London buisness as that came up for me as only $1400SGD one way. Getting to singapore would be easy and cheap enough