Following an unsuccessful attempt at farming out part of EPP 5 in late 1972, Shell resolved to continue exploring that permit area in its own right, subject to the offshore Designated Authority's approval of a variation in permit conditions, which was granted in the interests of maintaining an ongoing work programme in the Great Australian Bight area. This permit variation allowed the company to conduct one further seismic survey to try to firm up viable drilling objectives, prior to meeting a mandatory requirement to drill at least one technically challenging deepwater (i.e. in 800-1000 feet of water) exploratory well in 1974 (permit Year 6). The 1973 R7 detailed reflection seismic survey was designed to verify the structural validity of two deepwater structural leads, Potoroo and Bunyip, previously recognized from regional seismic coverage having only a 7 to 15 km line grid spacing. The subject evaluation report comprises the written outcome of a seismic remapping exercise based on interpretation of 402 line km of the new, high quality R7 data, following its integration with earlier, lesser quality seismic. After a brief statement of the Year 5 seismic programme objectives, the report discusses the target prospects' geological framework, interpreted reservoir objectives, respective structural mapping results, and identity of possible hydrocarbon source rocks with inferences about their associated petroleum generation and migration potential.