(It seems to me that they are not even going to attempt to answer the points raised by the Countess of Mar.)
Here is the response to the Countess of Mar's letter from Professor White and Professor Sir Simon Wessely:
Dear Lady Mar,
Thank you for your recent email and letter.
We are disappointed that your response quotes sentences from various papers and presentations without context to seek to confirm conclusions already arrived at; conclusions we do not share. We cannot even agree the meaning of terms, let alone a more detailed analysis of the literature. As one example, perpetuating or maintaining factors of a medical condition are not the same as the causes of the condition. So, treatments tested and shown to be effective in the PACE trial do not address the infection that may have started CFS, but do help patients address particular barriers to their recovery, which are often nothing to do with an original infection.
With regret, we believe that continuing a correspondence will not bring our views closer together.
Professor Peter White and Professor Sir Simon Wessely
The Countess of Mar's letter can be read here: