If it was burning you would be seeing smoke, when new Ford said the engine can consume upto 1.0 litre of oil every 600 miles, they always have been known for a appetite for oil. Expect the above figure to be higher now as thats when new. They do not suffer badly from stem seals, you can see though if you start up from cold you will see a blue smoke where the oil has got past into the cylinder also on overrun and then acclerating will show same thing.

Martin