The Pipes were never banned in Scotland; that's an old wives' tale.  The tradition was not originally Gaelic; bagpipes were widely played in England before they even reached Scotland, for what that's worth.  Highland dress was proscribed for a while (in the Highlands only) by the joint government of Scotland and England; not by the Wicked English, whatever later fantasists might like to believe.  Your teachers should probably consult some reputable historians.