I know that this probably sounds a bit official but all I want to do is thank you very much for the excellent work you have just completed. I know that the cost of this type of work seems a lot but we both know that most of what has been achieved is hidden. Once again thank you very much.
Firstly, may I say how pleased I am with all the work you have done at the above address and thank you for a truly professional job with great attention to detail.
Thank you for completing the work in our redundant boiler room which was accomplished to your familiar high standard. I was particularly impressed with the new door which was installed in somewhat difficult circumstances.