I have just had a burst within one of the flexible copper tails trailing from my old Kitchen Mixer Tap (Hot). These tails are fixed and not removable. I therefore went out and purchased a new replacement mixer tap however I notice that the contemporary designs have altered in the way they are secured to the sink. My old one has a single 1 1/4" or 1 1/2" threaded bush passing through the sink with a corresponding brass thin-nut securing it below. Newer designs are fastened with horseshoe plate clamped to sink using either one or two m8 threaded stud and Nut. My problem is how to remove the old Mixer. Were special Box Spanners ever made available for these as I can't see a way of unfastening without removing sink.