The Navarre group has four CGUs: two plants, a store network and an online sales business. Its headquarters houses the finance, legal and human resources functions shared by all the units; its research centre works almost exclusively for the two plants. An indication of impairment arises for the online sales business. The management accountant proposes testing that business on its own assets only, on the grounds that the headquarters and the research centre do not belong to it. Write a judgement memo on the treatment of corporate assets in this test.