The front section is definitely Shadow/Wraith II, so the only other option is that it is built on a Corniche base.
I have to admit that I filed this one as a Silver Cloud which is plainly wrong....
On checking my source again, it should be a Silver Shadow.
So, the fairest way is to award a point to Hiawatha (who originally guessed Silver Shadow) and another point to nicanary (who guessed Casale as the coachbuilder) and to thank ecurie for his additional information.
I hope this is satisfactory.....