I am no expert in this, but while saints' feasts may be transferred when they fall during Lent, I would be surprised to find that a Solemnity like the Annunciation has ever been transferred. It is not a saints' feast, rather a Marian and Christological feast of the highest level. Moreover there was the tradition that March 25 was the day of creation (vernal equinox) and of the new creation (Incarnation). I'd be surprised that it was ever transferred. Perhaps someone who really does know the answer can respond. And, of course, as someone point out, it always falls during Lent, so "transfer" would not be the right word. There are few saints days clustered near to the general range of Easter dates that would be similar. The saints' feasts that get transferred tend to be the ones in February or April which some years are within and some years outside Lent. The Annunciation is very close to Easter--nearly always within four weeks and there is even a tradition that placed the Passover in the year Christ was crucified on the vernal equinox, making the Triduum coincide, more or less, with the Annunciation. But I have no clear details on this.