Dear Mr Bau,
After a long journey, we returned to Munich yesterday evening.
We want to thank you for the organisation, which was very well done. We are very happy. Especially the guides were of very good quality. We have made some remarks which we will send you again with your questionnaire. Also, we will write about our positive experiences with you in an internet forum.
We wish you a lot of success with your travel agency and send our best regards.
Best regards,