This paper is an experience report that analyses the use of MDD techniques to create and maintain a new software system for a large financial company. At the time of writing, the system has been in production for over nine years, providing a platform to investigate the long term effects of the approach. Software development was performed by a team of engineers lacking a theoretical background on MDD, which we termed unorthodox practitioners. Using a mix of qualitative methods, an exploration is performed on their experiences in developing production software with MDD via practical experimentation. The paper has two main contributions. First, it provides more data on how MDD is used in industry, in particular by non-experts. Second, it employs prior analytical frameworks to analyse gathered data and extract insights on MDD adoption.