These files are not essential to the running of SQL Monitor and thus can be deleted. They contain logging information that could potentially be useful if SQL Monitor stops working. Even then we would probably be interested in only the most recent files.
Because we use Log4Net logging it might be possible to modify the "RedGate.Response.Engine.Alerting.Base.Service.exe.logging.config" file found at "C:\\Program Files\\Red Gate\\SQL Monitor 3\\BaseMonitor" in order to change the way our logging works. There's a section that starts with <appender name="RollingFile"... that has several settings relevant to the maximum size and number of old log files kept. If you wish to edit this it's probably a good idea to make a copy of the original first.
The following Apache documentation has examples under the RollingFileAppender section:
http://logging.apache.org/log4net/relea ... mples.html
Alternatively you can manually delete any old log files as required.