As has been mentioned many times before, the only reasons the Pendolino's are being repainted is because Angel wanted them repainting. Voyagers aren't being touched as they aren't due a repaint yet - there's no 125mph diesel designs at the moment anyway which can tilt.
Surely the Voyagers must be due a repaint very soon as are they even older than the Pendolinos? I.e. Circa 2002. And the leasing company would probably wish to protect their investment.