PLEASE Guide me through this ERD

Guys, I have spent a few days designing a ERD for a case scenario, I think the entities, relationships, multiplicity and cardinality are correct.

However I was wondering if you guys could have a brief look and guide me or please advise and correct me if i am wrong.

This design is ERD 1, so the many to many relationships aren't resolved yet and the notation is UML, I am using StarUML to design this ERD.

The files are attached below;

I hope you guys can offer me some advise..

Thanks alot...

From the scenario, I have deducted the following business rules, for easier reading

--------------------Staff rules--------------------------------------------------------------------------------------
1. Each branch has a designated manager who has overall responsibility for the branch and the employees in the branch

2. To help manage the branch, an assistant manager supervises the staff

3. Employees must inform Alpha Luxury Holidays about their previous work history, for example, the company details and the job details.

4. Employee’s job can only be: manager, assistant manager, sales assistant and administrator;

Constrains;
 Staff gender should be recorded as ‘M’ or ‘F’:
 The employee’s salary should be greater than £10 and not exceed £50,000.
 Staff salary must not exceed the Manager’s salary;
 Staff numbers should be generated automatically using a sequence and a trigger.

----------------------reservation rules-----------------------------------------------------------------------------

1. A customer can book many reservations;

2. The customer normally would inform the agency staff of the length of stay, inward and outward dates, the city and country they would like to visit, their preferred facilities and the type of resort as well as the number of passengers.

3. The customer must also inform the member of staff if they are only booking a flight or only accommodation or both.

4. Details of the staff who took the booking must also be recorded.

Constrains;
 Each holiday end-date should not be earlier than the start-date.
 Customer’s email address should have a @ symbol present to be valid;
 Details of the staff who took the booking must also be recorded;

-------------------------------invoice rules-------------------------------------------------------------------
1. Once the holiday reservation is booked, the customer is invoiced for the holiday;

2. Customer must pay the invoice in full, either by cash, credit card, debit card or cheque

3. All invoices must be paid at least eight weeks before the departure date;



CASE SCENARIO DOWNLOAD

oh geez, not you too