How to tell someone that you already left a gift for him
How to say the bit below in a proper way?

In appreciation to your continued help and support to me during the past five years, I ‘ve dropped by your office today to firstly thank you for your time and effort and secondly to present you a very small gift in person but unfortunately i found your office closed. As I will be flying tomorrow, I left the gift in a small box with your secretary.

Thank you

Question

How to tell someone that you already left a gift for him
How to say the bit below in a proper way?

In appreciation to your continued help and support to me during the past five years, I ‘ve dropped by your office today to firstly thank you for your time and effort and secondly to present you a very small gift in person but unfortunately i found your office closed. As I will be flying tomorrow, I left the gift in a small box with your secretary.

Thank you

Answer

That's almost perfect! 
The only thing I would change is 'appreciation _for_ your' and possibly 'flying _out_' ( or _away_)

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