I would guess the 332 was certified at SS4 - but don't confuse that with what the aircraft is actually capable of!
Can anyone confirm the standard Shell fit?
There isn't a "Shell standard" as such. The Brunei machines are SS5, with Malaysia having one at SS5 and one SS6. The SS5 machine will be upgraded at some point to the CHC standard. Given the conditions of the S China Sea, SS5 is perfectly reasonable.
As for the "Shell" Bristow S92s in the N Sea - I'm not sure but it looks like they are SS6 (there aren't many photos out there). The Nigerian machines have SS6.