The kappa structural phase of BEDT-TTF salts incorporating various anions X provides an extremely interesting series of layered-structure strongly-correlated materials, whose properties range from metallic phases with the highest Tc organic superconductors to insulating phases exhibiting almost perfect triangular-lattice antiferromagnetic frustration, with a resultant spin-liquid ground state that is stable down to at least 20 mK. The new HiFi spectrometer opens up the possibility to use level-crossing spectroscopy of the molecular radical states that are known to form in BEDT-TTF as a local probe of the electronic properties of this family of materials. The form of the field-dependent asymmetry and relaxation reflects interaction of the radical electron with its neighbours and T-dependent studies will be made to span the full range of electronic states within the kappa phase.