SEDOL[Code_?(Function[v,StringFreeQ[v,{"A","E","I","O","U"}]])]:=
Code<>ToString[10-Mod[ToExpression[Quiet[Flatten[Characters[Code]
/.x_?LetterQ->(ToCharacterCode[x]-55)]]].{1,3,1,7,3,9},10]]
Scan[Print[SEDOL[#]] &, {"710889","B0YBKJ","406566","B0YBLH","228276","B0YBKL","557910","B0YBKR","585284","B0YBKT","B00030","DUMMY"}]