With the exception of subjects like Citizenship, Critical Thinking and General Studies, most Unis are not as fussy about A level subjects as people assume. The Russell Group have now ditched their Facilitating A level list, as it was often misunderstood to mean that these were the only subjects they valued, which was never the case.
Where Univerities do have "non preferred" A level subjects, they will be upfront about it on their websites. This should hopefully end the debate about whether subjects like Sociology, Psychology or Law are "too soft" for top unis in the UK.