I saw a headphones that I use on the list: https://www.sonarworks.com/reference/headphones (it is Sennheiser HD 518) and I wanted to try it. After downloading and installing a trial version I couldn't find the preset. However, another presets with mark "NEW" are presented in a folder: Sennheiser HD 206 | Sennheiser HD 280 Pro | etc.
Did you forget to add "Sennheiser HD 518" to release version? Or it is available only in a paid version?