Zupacars Ltd sells cars, car parts and petrol from 20 different garages. Each branch has up to 20 staff working there, although most of the accounting systems are centralized at the company's head office. Branches enter data over a network directly into head office systems. Because of the nature of the business which deals in cash selling petrol, oils and accessories and the risks of theft of easily saleable car parts, there is an internal audit department which frequently advises and implements controls within those systems. It also carries out spot checks as well as more formal audit routines at the branches.
The internal audit department comprises six staff, all of whom have been employed at Zupacars for a minimum of five years and some for as long as 15 years. In the past, the Head of Internal Audit appointed staff within the department. The chief executive officer (CEO) is responsible for appointing the Head of Internal Audit. The Head of Internal Audit reports directly to the Finance Director. The Finance Director also assists the Head of Internal Audit in deciding on the scope of work of the internal audit department. You are an audit manager in the internal audit department of Zupacars, currently auditing the petty cash systems at the different branches. Your initial systems note on petty cash contain the following information:
1. The average petty cash balance at each branch is £5,000.
2. Average monthly expenditure in each branch is £1,538, with amounts ranging from £1 to £500. It is often used to buy repair parts from wholesalers if they are not in inventory or to pay contractors such as vehicle painters or specialist electricians.
3. Petty cash is normally kept in a lockable box in the administration office at the branch. It is often left open during the day so that staff members can obtain cash if needed in the absence of the branch administrator.
4. Vouchers for expenditure are signed by the person incurring that expenditure to confirm they have received reimbursement from petty cash.
5. Vouchers are recorded in the petty cash book by the administrator at the branch who is responsible for entering transaction details into the Head Office systems via the interbranch network. The voucher records the date, reason for the expenditure, amount of expenditure and the person incurring that expenditure.
6. Petty cash is counted every month by the administrator, who is in charge of the cash. The petty cash balance is then reimbursed using the 'imprest' system.
7. The reimbursement of petty cash is by a cash transfer delivered from Head Office.

Required:
(a) Explain the issues which limit the independence of the internal audit department in Zupacars. Recommend a way to overcome each issue.
(b) Explain the internal control weaknesses in the petty cash system at Zupacars. For each weakness recommend a practical control to overcome that weakness.