The DIADEM project aims to develop a web-based application in the form of an Expert System (ES) to assist cognitively impaired older-adult users in the task of interacting with and completing online transactions. Having recently developed the first experimental version of the application, this study reports on the preliminary findings of user trials carried out in three European countries top evaluate this early version of the application. Of the 94 users that took part in the trials, 77 were identified as users that were likely to present with some degree of mild cognitive impairment, and thus were included in the analysis stage. The key findings of the study indicate that users of DIADEM assisted form filling seemed report comparatively high-levels of satisfaction, particularly when considered against what is considered a typical level of satisfaction for this user group. Furthermore, as a result of a statistical analysis, the application appears to provide significantly increased levels of assistance for users presenting with higher levels of cognitive impairments, and therefore achieves its goal of catering for this particular target user group.