The comms failure procedure you speak of is outlined in the NZAIP rather than an Airline specific SOP. ENR 1.15 - 8 Diversion
I'm familiar with a few Airlines who have a requirement to divert after 2 unsuccessful approaches, although even then, the PIC can exercise their authority to conduct a 3rd.
Personally, I'm not a fan of trying to create SOP's in place of good airmanship.