Thank you very much for the hard work you did yesterday, the garden looks much better...
Thanks for doing the work on the garden, it looks great!
Thanks very much for all your hard work. I’m extremely pleased with what you've done; not only in the amount, quality and tidiness of what you've achieved but also the way in which you got on and did the job with minimal involvement from me.
Thanks very much for a great job!
Thanks to Chris for a good day's work! It looks lovely.