Ystyriodd y Goruchaf Lys nifer o faterion, ond o diddordeb penodol o ran y setliad datganoli yng Nghymru oedd y ffaith i ddilysrwydd y Ddeddf Albanaidd gael ei herio ar sail yn y gyfraith gyffredin. Dadleuodd yr apelwyr (cwmnïau yswiriant) fod Deddfau Senedd yr Alban yn agored i adolygiad barnwrol ar sail eu bod yn ddefnydd  afresymol, afresymegol neu fympwyol o’r awdurdod deddfwriaethol a roddwyd i Senedd yr Alban gan Ddeddf yr Alban 1998.
There were a number of issues considered by the Supreme Court but of particular interest for the Welsh devolution settlement was the fact that the validity of the Scottish Act was questioned on common law grounds: it was argued by the appellants (insurance companies) that Acts of the Scottish Parliament are open to judicial review as an unreasonable, irrational and or arbitrary exercise of the legislative authority conferred by the Scotland Act 1998 on the Scottish Parliament.