Is this growing indoors? The reason I ask is the flower bud has not developed the way a normal lavender flower bud would if grown outside and this will limit correct identification. The leaves are not enough of a distinguishing feature as both L angustifolia and L. x intermedia have similarly sized and shaped leaves.

As to ID'ing a specific cultivar, that gets even more tricky :-) There are several 100 cultivars of English lavender and only a few less of lavandin and many are quite similar in appearance. You would need something really distinct for someone to confirm a specific cultivar!!