Blaupunkt Hamburg radio removal/fitting

Can anyone help me? Im trying to install a Hamburg radio into a MK1 but cannot get it in… Basically to each side of the head unit there are two metal plates which obviously lock the stereo to the dash but I cannot remove them. It feels as if I try to remove the facia from the unit that I'm going to break it, but is this something I need to do to remove the steel brackets…?