"May we take this opportunity to thank you for your assistance in bringing this matter to a swift conclusion"

"May we take this opportunity of thanking you for your co-operation in completing this matter"

"Once again my thanks for your fast, efficient service"

"Thank you for all the trouble you have taken"

"Thanks for all your help and advice"

"Thanks for all your hard work"

"We are both incredibly grateful for your current progress"

"Thanks for all your hard work and expertise over the past 5 months. I would have no hesitation to recommend you to anyone"

"Thank you once again for your efforts on my behalf"

"Thank you for all the work you have done for me"