Sjo4, out of curiosity: were you asked to do this?
I've never had to for any UK course (I've been on a few), even for the MA. Yet my UG records are not even in English, but in French. Once or twice I asked if I had to get them translated or anything, and the answers were: "oh, don't bother, save your money, we'll figure out what this is worth!" and "no, don't worry, we're quite familiar with these"...
Did I get a "neighbours' favour" of some sort? That would surprise me, but hey... I would have imagined it to be even easier for US transcripts, given they're already in English.