Young9719

Hi I wonder if anyone can help. Just bought a mk1 s-type after years of wanting one. Bodywork and engine are 100%, however failed mot on rear sub frame. ..has 2 small holes and one bush needs replacing. Any ideas....if I buy a second hand sub frame will a later model part fit a mk1 car. Just want to be sure. Anyone know of a good dealer to go to for this. Thanks Paul