The Student Learning Advisory Service offers support with referencing and avoiding plagiarism. The team has developed several excellent guides accessible on their webpages. You can also schedule a one-to-one appointment with them or ask a question through their appointments page.
For practical MHRA referencing guidance, the recommended resource is Cite Them Right, an interactive guide designed to assist you with referencing and avoiding plagiarism. You can also access the MHRA Style Guide Online, which serves as the official guide from The Modern Humanities Research Association.