Most English judges have risen through the lower ranks of the legal profession so
Holbourn's Sources of biographical information on past lawyers (1999) Ref Bibl Cw UK H723b.
Brooks & Heber: My ancestor was a lawyer Ref Bibl Cw UK B814
are good starting points.
The LawBod's collection of autobiographies & biographies of English judges is shelved on the main Reading Room Floor with shelfmarks beginning KB.
The judiciary have also been the subject of collective biographies - the boxes on this page show some of the most well-known.
You may also find some useful material in works looking at the judiciary as a body. These are likely to be either in the Legal Hist.section of the LawBod - or possibly even in the Bodleian's History Reading Rooms. For examples see the box called Texts on Topic on this page.
Don't forget articles in journals: use the Index to Legal Periodicals and Bibliography of British and Irish History to find them!