You are an audit manager of Wrunne & Hyde LLP and you are currently planning the audit of Macedon plc Co., a company which develops and manufactures health and beauty products and distributes these to wholesale customers. Its draft profit before tax is $6.4m and total assets are $37.2m for the financial year ended 31 January 2022. The final audit is due to commence shortly and the following matters have been brought to your attention.  Research and development Macedon plc Co. spent $1.9m in the current year developing nine new health and beauty products, all of which are at different stages of development. Once they meet the recognition criteria under IAS 38 Intangible Assets, Macedon plc Co. includes the costs incurred within intangible assets. Once production commences, the intangible assets are amortized on a straight-line basis over three years. Management believes that this amortization policy is a reasonable approximation of the assets' useful lives, as in this industry there is constant demand for innovative new products.

Depreciation: Macedon plc Co. has a large portfolio of property, plant and equipment (PPE). In March 2021, the company carried out a full review of all its PPE and updated the useful lives, residual values, depreciation rates and methods for many categories of asset. The finance director felt the changes were necessary to better reflect the use of the assets. This resulted in the depreciation charge of some assets changing significantly for this year.

Required:
(a) Describe substantive procedures the auditor should perform to obtain sufficient and appropriate audit evidence in relation to Macedon plc Co.’s research and development expenditure.
(b) Describe substantive procedures the auditor should perform to obtain sufficient and appropriate audit evidence in relation to the matters identified regarding depreciation of property, plant and equipment.