Low-dimensional quantum magnetism continues to be of great theoretical and experimental interest, as reduced dimensionality supports strong quantum fluctuations which can result in novel excitations and critical behaviour. Here we propose to complete our investigation of a series of molecular 2D quantum Heisenberg antiferromagnets (2DQHAFs) with substituted non-magnetic ions. This is a continuation of experiment RB1320234, in which the pristine material and nominal 8% Zn-substituted system were measured. We have shown that muons are a powerful means of exploring the magnetic order and disorder in this system and we now seek to measure more diluted compounds with different Zn concentrations in order to complete our investigation of the phase diagram of this novel 2DQHAF.