Dear Mr. Johnson
Thank you very much for your letter of 3 May 2004.
We wish to offer our sincere apologies for the long delay in replying to your letter. We have recently moved our headquarters to a new location in the south of city and this has resulted in some considerable delay in replying to enquiries. The move has now been completed and I can assure you that there will be no more delays in the future.
The catalogue you require are enclosed and I hope that you will continue to use us as your main supplier.
Your sincerely