Since you have completed your 2nd year LLB in 1975 and could not continue your final year, the process to complete your 3rd year now depends on the university’s regulations. Most universities allow students to rejoin or appear as private or external candidates if a long gap exists, but policies vary. You should contact the university’s law department or the examination office directly, explain your situation, and request guidance on completing the final year. They will inform you about eligibility, documents required, and whether you can enroll in the pending year or appear for exams as a special case.