Perhaps this would be one of the "Chi Shin Weng Chun" branches originally from Weng Chun precinct of Fatshan? Chi Shin was a Shaolin Abbot who later hid on the Red Junk. The system shares some techniques with the Wing Chun/Tsun styles but is distinct (even uses different Chinese Characters).
i think people just made up the the name. branch doesn't matter. who care .
according to the myth or origin of wing Chun. The shaolin (Sil Lum= shaolin = little forest) nun Ng Mui is creator of Wing Chun. she knew the weakness of shaolin Kung Fu and work to create new system that would be effective, quick to learn. She alone did not create the system though, from my reading, she did it with 4 or 5 other monks. the system was then taught to Wing Chun. and the long pole was added later on.
Some sifu want their students to remember the root so they call it SIL LUM WING CHUN.