Ok, I actually didn't see the dogs, only heard loud aggressive barking at https://www.openstreetmap.org/node/3741053486 , and I was too scared to go inside further (have previously been chased by dogs in indigenous villages while surveying before).

I have recently tried to visit again via the other side (entering from Nam Sang Wai Road instead of Ho Chau Road), and encountered a gate at around https://www.openstreetmap.org/node/5043794717 . Not sure if this is the one this note is referring to.