Your firm, Tickett & Wrunne is the external auditor of Cornflower Ltd (Cornflower). You are the audit manager and are conducting your final review before passing the file to the audit engagement partner. The audit file contains the following relevant information:
(i) Cornflower's core business has been the manufacture of plastic piping and fittings for the plumbing and construction industry. Cornflower is developing a diverse business as a manufacturer of plastic roofing and sheeting and as a plastics Moulding business for the motor industry.
(ii) In its core business, Cornflower has seen its revenues decline by over 25 per cent and its gross profit margins worsen over the last three years. These effects have mainly been caused by increasing competition from overseas competitors who have lower operating costs. This has resulted in trading losses for Cornflower in each of those years, including the current year ended 31 December 202X. Cash reserves however are strong enough, so far, to keep the company going for the foreseeable future. Cornflower underwent a major factory reorganization during the year to enable it to diversify its activities away from its core business and concentrate on its new sheeting and Moulding business. This reorganization, which was completed in November 202X, was partly funded by a large bank loan. The profit and cash flow forecasts prepared by the company to support the application for bank finance indicated a return to profitability for the year ending 31 December 202Y.
(iii) During the year, one of Cornflower's major customers went into administration. Cornflower has claimed from the customer's administrator both for recovery of the outstanding debt and for the return of product which was supplied to the customer on a sale or return basis. Cornflower has negotiated a sale of the returned product to another of its customers, dependent upon the successful recovery from the administrator of the product in question. Initial indications from the administrator are that 50 per cent of the outstanding debt is likely to be recovered by Cornflower. The administrator is also pursuing the recovery of the sale or return product on Cornflower's behalf. Cornflower has taken a favorable view and has included the receipt of 50 per cent of the debt and the proceeds of sale of the returned product to its alternative customer and has made a small provision for the remaining debt as a bad debt. It has also included these amounts as cash receipts in its cash flow forecast for January 202Y.

Required:
(a) Briefly set out the reasons why work performed by audit staff during an audit is reviewed by other more senior staff or the engagement partner.
(b) Comment on the key matters which might arise as a result of your review and any implications for the audit opinion.