Legal information systems face critical challenges safeguarding sensitive client data while navigating multi-regulatory professional workflows. Current Legal Information systems employ uniform calendar-based retention policies that contradict GDPR data minimisation mandates, unnecessarily exposing client information across multi-stage legal transactions. This research proposes the Stage-Based Contextual Data minimisation (SB-CDM) framework, a progressive minimisation methodology for legal services that operates at the individual data-element level rather than the category level, reconciling five overlapping regulatory frameworks through automated precedence hierarchies and trigger-based stage recognition. Comparative evaluation with the current uniform 7-year retention baseline approach reveals a reduction of 49% of data volume, a reduction in exposure time of 1,139-days (44.6%), 50.3% of element-specific minimisation granularity and a retention justification coverage of 100% in two residential conveyancing scenarios. The framework advances information systems (IS) quality by operationalising transparency and accountability requirements for systematic compliance in complex regulatory settings. While developed for conveyancing, the methodology provides a template for multi-stage professional services navigating complex compliance environments.