Length of uint8_t* const array
sizeof() gives the number of bytes. You are looking for membersof(). It is often defined as:

#define membersof(x) (sizeof(x) / sizeof(x[0]))


And in the example above:

for (int i = 0; i &lt; membersof(neighbourSet); i++) {
     //do something for each PEER. 
     delay(50);
}  


For more practical C/C++ macro and type extensions please see the Cosa Types.h file.