On the V8 I doubt you can source the "Recommended" oil from other than LR @ R70 odd / Liter x 8. Oil filter is R 288.
Intermediate (dealer) service will be charged at +- R 1300, plus they will stamp your book.
The latest oil and alternative is as follows :
SAE 5W-20 engine oil meeting
If unavailable, SAE 0W-20
engine oil meeting Jaguar Land
STJLR.51.5122 may be used.
Also remember that oil that is "suitable for use" is not the same as oil that is "approved for use" (Marketing trick).