This study explores the role of teachers' perceptions of digital personalised learning (DPL) tools in their intention to use and actual usage of these tools in the classroom. Utilizing the Technology Acceptance Model (TAM), we address two gaps in the literature: the limited investigation of DPL in real-world settings and the reliance on self-report surveys to study TAM. We collaborated with 15 schools in Flanders (Belgium) to assess the i-Learn portal, a newly developed DPL tool. Our research objectives were to examine the relationships between teachers' perceptions of usefulness (PU), ease of use (PEU), behavioral intention to use (BI), and actual usage. We employed a mixed-method approach involving self-report surveys, focus group interviews, and log data analysis. Results indicate positive associations between PEU and PU, PU and BI, and BI and actual use based on survey data. However, there was no significant relationship between BI and actual use when measured through log data. Notably, a positive correlation was found between survey-based actual usage and actual usage as measured through log data. These findings emphasize the importance of considering actual usage data and qualitative interviews alongside self-reported data when evaluating DPL tools in large-scale projects. The study contributes to the alignment of future educational technology (EdTech) tools with teachers' perceptions and actual usage patterns.