Dear Auto Trader,

I am just writing to say a very big thank you for all the help you gave us yesterday in sorting out an advert for Thames Valley Autotrader. We didn't realise the deadline was yesterday. 

As you will have realised I am not exactly a whizz on the computer and despite starting the process rolling yesterday morning, I was still battling at the last minute to get the advert to you.

So I just wanted to say a very big thank you for all your patience and time and for really putting yourself out to help us get the advert done.

You are very kind and professional.

Kind regards,

Janet Brewer.