The wreck listed on wrecksite.eu as the Seven Seas is not the Seven Seas. Wrecksite references Dive Sussex - Kendal McDonald's position, while Neil Maw's WW1 Channel wrecks suggest it lies a mile to the east, and SIBI likely used Kendal's coordinates at 50 38 E 00 15. Survivors' accounts place her roughly 6 miles off Beachy Head, aligning with the aforementioned positions.
The wreck in question has only one boiler, whereas the Seven Seas had two, in addition to a two-cylinder engine, unlike the Seven Seas' three-cylinder.
Regarding the identity of this unknown wreck, I initially considered it might be the SS Coath, but research revealed that the Coath had two boilers.
So, I don't know what the wreck is. Or where Coath is. Or where the Seven Seas is either. Shipping lanes probably..