The multiferroic metal-organic perovskite copper guanidinium formate is structurally analogous to KCuF3, and like its inorganic counterpart is a good realisation of the S=1/2 1D Heisenberg antiferromagnet. In this material, however, our previous work (LET, ISIS) has demonstrated that even in the 3D ordered phase there are no well-defined spin-waves. Instead, there is a clear excitation continuum, suggesting that spontaneous magnon decay plays an important role in this system's dynamics. Theoretical research has shown that such a decay of spin-waves can arise if the magnetic structure is noncollinear. Therefore, to complete our study on this material, we propose to measure the magnetic structure of CuGF. Due to symmetry constraints, this requires the use of polarised neutrons: this proposal calls for both unpolarised time on D9, to determine the nuclear structure in detail, and polarised measurements using Cryopad on D3. As well as being a potential example of non-collinearity shortening magnetic lifetimes, the data obtained will help to elucidate complex magnetic behaviour in functional MOFs and the ways in which their magnetic properties differ from their inorganic analogues.