Last time I had a cold start problem it turned out to be the thermal time switch at back of inlet manifold (brown plug) I was lead to believe that it sences the water temp in back of inlet and then intern opens or closes the cold start valve. Any how after changing it she would start and tick over sound from cold but then developed a hot starting problem lol. That turned out to be the fuel vapourising in the injector pipes and losing pressure new fuel pump and set of second hand injectors solved that one lol. You got to love the old RS's lol hope you get it sorted mate