Dear Lynn,
I'm writing you this letter to ask you to kindly do a favour for me.
As you will remember, I stayed at your home 3 days ago when I participated in a business seminar in your city.
Unfortunately when I was packing up my belongings for my trip back to the UK, I completely forgot about a file with important documents inside. If my memory doesn't fail me, I left it on the table in the room that I stayed in. The file has a red cover and a tree-coloured logo on the top-right corner.
I would be very grateful if you would send me the file by post. I will forward my UK home address to you by email. I'll pay for all postal costs related to sending the file from Australia to the UK.
Thank you in advance,
Betty.