The design of learning opportunities is an integral part of the work of all educators. However, educators often lack the design skills and knowledge that professional designers have. One of these basic skills is related to the evaluation of produced artefacts, an essential step in all design frameworks. As a result, evaluation of learning activities falters due to this lack of knowledge and mindset. The present study analyses how in-service educators perceived and accomplished an evaluation activity aimed at promoting assessment prior to enactment. Heuristic evaluation is an inspection method considered to be one of the easiest to learn and yet is efficient, time and cost effective. These characteristics make it suitable for the design work of educators; which is, above all, practice-driven and practice-oriented. Results show that educators grasped the value of such an activity (solving possible second-order barriers) but struggled to understand how to do the specifics of the task (first-order barrier), which was to define their own set of educational heuristics. Based on the lessons learned, the paper finalises with a proposal for a design task to include evaluation to support learning design; empowering educators to assess both existing learning activities and ICT-tools as well as their own designs.