A good letter with only minor errors, mainly missing articles (a, an or the) and only a couple of spelling errors and only one verb tense error which is a very good improvement on your last letter. Just note after you have used ‘Sir’ at the beginning of the letter you don’t use it again at the beginning of sentences. I think you were a little unsure of what more to say in your letter so we can work on thinking about more ideas when planning your letter before you start writing. That way you will have plenty of things to write about to show the examiner your broad vocabulary knowledge which you do have as it is clear from your speaking in class. It is just a matter of thinking quickly of what to say and with practise you will develop this skill.
See my feedback below. The first document (Edited Version) has the editing marks so that you can try and correct your work yourself. The second document (Corrected Version) is the corrected version so that you can see the corrections I have suggested.