OK here we go.

taking the positions of the alphabet in the name BIG STE ,times them 
by 11 (number of letters in Stephen Holt) and add them together.

22+99+77+209+220+55=682

682-(6(number of letters in Big Ste)*2(number of A-Levels he 
has))=670

670-4(number of consonants in Big Ste)=
.
.
.
.
.

666.