Do you have any blue smoke coming out of the exhaust? If the oil is getting past your rings or there is an issue with the turbo you will get blue smoke how many miles has the car done?
as long as the turbines are supported you will get pressure on spool up.
3 litres in 1500 miles is a lot, if it is coming past the rings your plugs could be fouled - what colour are they?
Is the coolant fluid clear, no milkiness? Might be worth doing a sniff test just to make sure in order to check head gasket??