Having looked at all the movement rules, and at Feigned Flight and Page 41, I have come to the conclusion that you can institute a feigned flight even if you have made tactical, march or spontaneous moves. This is on the basis that feigned flights are flee outcomes, which always take place as the last action of a bound and are not conditional on troops having moved before hand.
For example- You can move into combat using a full tactical move, be beaten and having then to flee if your a certain troop type. All a feigned flight allows you to do is to flee without having had a combat or flank attack/march outcome etc.