Question: when did charles buy gad's hill place
[{'answer': 'March 1856', 'provenance': [{'wikipedia_id': '7795498', 'title': 'Gads Hill Place', 'start_paragraph_id': 4, 'start_character': 685, 'end_paragraph_id': 4, 'end_character': 695, 'bleu_score': 1.0, 'section': 'Section::::Dickens.\n'}]}, {'provenance': [{'wikipedia_id': '7795498', 'title': 'Gads Hill Place', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 947, 'bleu_score': 0.9891594913313011, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 9622113557584103683}, 'section': 'Section::::Dickens.\n'}]}]