Watch List notes:

USA Proof Sets (12) 1978S (3), 1979S Type I (3), 1980S (3), 1981S type I (3) nFDC to FDC 1979 and 1980 sets retaining practically full mint brilliance, the 1981 sets with some toning, in the black cases of issue

Estimate: 60-80 GBP