"Hi Andrew ... just wanted to say thank you very much for the 'Lima' lights which we are delighted with. They look fantastic and we are very grateful to you for letting us have them at the reduced price.
I made a call to your company this morning whilst the electrician was fitting them up because the dimmer switch wouldn't work on the first one he connected. However, a call to your technical staff assured us there was no reason why it shouldn't have ... and it turned out to be a faulty dimmer switch!
So thank you again for a brilliant service!"