Manx

If you're going to write anything, I would only write a request for a meeting - initially without the guy who reported this as a problem (obviously such a request should not be phrased that way, simply request a meeting so that you can speak to the situation). Email/letters are VERY poor methods of communication, particularly in situations such as this.

On another note, the emails/letters that were sent reporting the problem seem to show a high level of arrogance (for instance, the author lumps himself in with managment on a number of occasions as well as speaking for many other people in the department). I don't get the impression that the person who has reported this as a problem is a part of management or is able to speak on behalf of many other people in the department. This is both a sign of the poor communication inherent to email and possibly something that could work in your favor (management doesn't like being told what it has to do by non-management, and rightfully so).

The key is to present as dispassionate a response as possible. Sincerity and clarity are key. You're not going to achieve either via email/letters and you're better off initially presenting your case without your accuser present.