I do not normally enclose a letter of thanks with a returned invoice but on this occasion I wanted to thank you and your colleague Duncan, for the time and effort you both put in on my behalf. I am also most appreciative that you were very careful to give me a totally honest appraisal of my position. Such an attitude is rarely trun in the commercial world and less frequently true in the professional world than I would like.
I am most grateful and will contact you in 12 months time.