The Question and Answer section for Dr. Jekyll and Mr. Hyde is a great resource to ask questions, find answers, and discuss the novel.
I see no evidence of Mr. Enfield's occupation in the text. We do, however, know that he is a Victorian gentleman and Utterson's cousin.
From the text:
His friends were those of his own blood or those whom he had known the longest; his affections, like ivy, were the growth of time, they implied no aptness in the object.
Mr. Utterson has a small group of very good friends, with...
MR. UTTERSON the lawyer was a man of a rugged countenance, that was never lighted by a smile; cold, scanty and embarrassed in discourse; backward in sentiment; lean, long, dusty, dreary, and yet somehow lovable.
"I incline to Cain's heresy," he...