Southern Bridge is actually named https://www.td.gov.hk/en/traffic_notices/index_id_74356.html 
Ref https://www.youtube.com/watch?v=s0IUhoYbsCY
https://www.landsd.gov.hk/doc/en/mapping/ehkg/individual_PDF/3_Index_Content.pdf#page=22 (don't use) 
https://www.youtube.com/watch?v=pSl8h1nsTTE
You can see signs for TKO CBB. I forgot for Southern Bridge. 