The development of decorated metal-organic frameworks (MOFs) is important for enhancing gas storage and mixed gas separation systems. This proposed QENS study will investigate the methoxy functional group (-CH3) behaviour in a MOF system and the changes it exhibits upon gas loading. The methoxy functionalised MOF, MFM-300(InOMe), is isostructural to parent, non-functionalised MFM-300(In) enabling the role of linker decoration to be easily attributed to the changes that we anticipate to observe. The proposed study aims to reveal the full nature of methoxy behaviour in an ordered crystalline system, focussing on the potential for methyl rotational tunnelling and how this phenomena changes upon gas loading by analysing the QENS data together with our prior MD, INS and IR studies.