It's too clean sounding. Geru still had her nodules rasp so had yet to become the multi (decimal point) octave range vocalist we know and sometimes tolerate today.
I once used that intro in a 'guess the song from the clip' style contest - nothing else, just that with the volume boosted. No-one got it. But. having listened to the amplified version several times as a result, I was convinced it was Mel B.
I do love both Emma and Mel C knowing they'll never get the truth from them on it and almost acknowledging Geru claiming to have wrote everything herself.