The overun burning is probably the valve stem seals so new seals will probably sort that mate. Most leak somewhere as Tabetha says, but remember that Fords introduced a 'check oil daily' sticker on the F/G plates for a very good reason... if yours is original it will have one of these on the pulley cover and another inside the fuel cap.

Mine uses up to half a litre on a fast n hard 250 - 300 mile motorway run incidentally. Always has - and had it since 92 Oil does weep from the cam seals and the lower front crank seal... they harden up with lack of use and mines only done 57k.

If I recall correctly I was told that 0.7 litre is the difference between full and bottom of the dipstick - just checked the Ford spec and it ain't in there. It does seem to fit with what I use though.

Hope this helps,

Andy