The FDR refinement-checking tool, available free for academic purposes. [5] relies fundamentally upon the congruences between operational and denotational semantics for CSP, in order to determine a denotational property by exploring an operationally presented system. But the calculation of the standard structured operational semantics of complex systems proves a bottleneck in the performance of the tool, and so we compile a custom inference system for each case, optimised for facilitating execution of the relevant queries. Recent developments have revealed how these calculations can be re-used in restructuring systems to maximise the potential for hierarchical compression and for export to a related probabilistic formalism.