Dear Mr and Mrs Jackson,
Thank you very much for your letter. I am writing to give you the information you asked for.
Firstly, I need to tell you about my travel arrangements. I am arriving at Gatwick Airport on 14th July. My flight number is BA 451 and it lands at four thirty in the afternoon. It is very kind of you to offer to pick me up from London, but I have already arranged to take the train to Cardiff. Perhaps you could meet me at the station. I could phone you when I arrive.
As far as food is concerned, please don't go to any trouble. The only thing I don't eat is mushrooms. Besides, I am looking forward to trying British food.
Finally, there are one or two things I would like to ask you. What is the weather like in Wales in August? How cold is it? Do you think I need to bring warm clothes? Also, I was wondering if you had a computer that I could use while I am staying with you, or should I bring my laptop?
Thank you once again for your letter. I am looking forward to meeting you in July.
Best wishes