The purpose of this ROI is to invite suitably experienced parties to submit their proposals with information on their skills, services and experience in providing mesoscopic transport models. This information is requested so that we can shortlist organisations interested and capable of delivering these services for the RFP procurement stage. The ROI also requests feedback from the market on some HTM scope issues. This feedback will not be scored and will be used to inform the final HTM scope of work used for the RFP stage.