Dear :

Thank you very much for giving so much help to our Sales Manager [name] while he was in [country/area].

must have already written to you expressing his gratitude, but I would like to thank you on behalf of the whole company. The information you provided and the contacts you helped him to establish are most useful to our export efforts in the area. We wish to have more help from you in the future.

If I can offer you any similar service, please feel free to let me know.

Yours sincerely,

[name]

[title]