Rolls-Royce Control Systems supplies engine control and monitoring systems for aviation applications, and is required to design, certify, and deliver these with the highest level of safety assurance. To allow Rolls-Royce to develop these systems, which continue to increase in complexity, model-based techniques are now a critical part of the software development process. At MODELS 2021 we presented early experiences with using and maintaining a bespoke domain-specific modelling workbench based on open-source modelling technologies, including the Eclipse Modelling Framework (EMF), Xtext, Sirius, and Epsilon. In this paper, we build on our previous paper with further insights, new challenges and lessons learnt as we have advanced and matured our domain-specific solution. We also discuss our experiences with moving towards web-based modelling tools based on open-source technologies including Sirius Web, Eclipse GLSP and Eclipse Theia. Rolls-Royce intends to use a selection of these technologies to build a web-based modelling workbench, which will be used to architect and integrate the software for future Rolls-Royce engine control and monitoring systems in a collaborative way.