From the handbook
"Oil specification - petrol engine
An oil of 5W-30 viscosity meeting Jaguar
specification WSS-M2C-913 - A or B is
preferred. Where this is not possible, oil
meeting API SJ/EC and ACEA A1 98 or A3 98
may be used.
SAE viscosity rating - For climates ranging
from -30°C (-22°F) to +50°C (+122°F), the
following oil viscosities may be used:
0W-30
5W-30 (preferred)
0W-40
5W-40"
"Oil specification - diesel engine
An oil of 5W-30 viscosity meeting specification
WSS-M2C-913-B must be used in all vehicles
fitted with a diesel engine.
For top-up purposes only, where oil of
specification WSS-M2C-913-B cannot be
found, ACEA B1 or or ACEA B3 specification oils
may be used."
"Jaguar recommends Castrol"
Note the diesel engine oil statement
"WSS-M2C-913-B MUST be used ......." rather than the "PREFERRED" for the petrol engines.
As Robby points out, WSS -M2C-913-C is a later spec and surpasses the B spec.
So it's as good, if not better.
I wouldn't deviate from the diesel oil specs, turbos are designed to run on a certain grade and spec, they don't like the wrong stuff.