The Baron Returns by John Creasey

John Mannering (aka 'The Baron') pulled his scarf up so as to hide his face. A casual observer from a window above would probably not even notice him. The finest jewel thief in London was utilising all of his skills to nail a crooked Solicitor. Mannering's friend could be ruined by documents contained in the lawyer's strong-room and so he risks all, especially his freedom, to get them back.