Copied this from my xkr workshop cd manual, interesting it states:

Operation under varying conditions can frequently be misleading. A vehicle that has been run for several thousand miles on short trips or in below-freezing ambient temperatures may have consumed a "normal" amount of oil. However, when checking the engine oil level, it may measure up to the full mark on the oil level indicator due to dilution (condensation and fuel) in the engine crankcase.
The vehicle then might be driven at high speeds on the highway where the condensation and fuel boil off. The next time the engine oil is checked it may appear that a liter of oil was used in about 160 km (100 miles). Oil consumption rate is about one litre per 2,400 km (1,500 miles).
1 litre every 1,500 miles would that be exceptable, my xrk takes a bit now and again but i be on the power alot.

 

Neither my XJR or my XKR and now my FtypeR use/used any noticeable amount of oil.. I would have been concerned if I used a litre every 2,400. although I have had other cars that did use a fair bit of oil. I guess I have always considered the 5.0 to be such tight tolerance engine that oil useage would be very minimal.
Lawrence.