Covering letter - extension application

Hello All
I am looking for a covering letter which can help me in drafting my own covering letter.
I know all covering letters will be different and will be specific to the individual case. But it will help in getting ideas in how to draft a good covering letter.

Please see this which we will be following.

http://www.immigrationboards.com/uk-tie ... r#p1341925

Also bear in mind that a covering letter has no legal bearing on your application and will not be a replacement for the required information and documentary evidence by the HO. I suggest you provide this letter only and only if your case is complex as some evidence here on the forum suggests that providing extra irrelevant documents and information sometimes will NOT work in your favour.