Letter Writing - FULL Format - Situation 2 - from an individual writing for an organisation to another organisation

SITUATION 2

Let us pretend that you are writing on behalf of / for an organisation to another organisation.  So in this case the full format should be:

St. Hilda's Secondary School [You are working for this organisation]
3 Amanda Road Street 1
Singapore 123456

11 July 2010

Mr. William Shakespeare Singh [Let's say you know the name of the recipient.]
The Director [Don't forget]
St. Peter's Seniors' Home
4 Zion Road
Singapore 678910

Dear Mr. Singh [Surname only]

Donation From A Generous Contributor [topic / reference]

Paragraph 1
Paragraph 2
Paragraph 3
Paragraph 4
Paragraph 5
or even Paragraph 6

Yours sincerely [because you mentioned the name of the recipient, Mr. Singh]
YOUR SIGNATURE
Wong She Hau [Your name]
Student Volunteer [Your position]
St. Hilda's Secondary School [Your organisation]