Oxford, Cambridge and one or two other places do a two year senior status law degree for graduates which is both expensive and extremely competative.
However when most people refer to a conversion course they mean the course known as the Graduate Diploma in Law alternatively known as the Common Professional Examination.
This course in offered in several cities by the College of Law, a private provider BPP, and a number of universities most of which are post-1992 universities.
Except where law firms are meeting the cost, they generally do not care where the GDL is undertaken.
Entry requirements are normally a degree, a pulse and a cheque book.