WSO or WSOp
WSO is the new name for navigator and any commissioned aircrew who is not a pilot, whilst WSOps are all senior NCO aircrew, sometimes referred to as NCA, non commissioned aircrew.
The WSOp branch is further split into 3 groups,
1. EW being the old air electronic operator, AEOp, and normally works on the Nimrod but also AWACs, SAR Sea Kings, Aster.
2. AL being the air load masters on the transport and support helo fleets.
3. Air Eng, supposedly a dieing trade due to glass cockpits, as the modern air force has loads of new aeroplanes!
Hope this helps, but if you're really interested, use your noggin and get down to the CIO and get the leaflets.
RR