The hyperhoneycomb lattice can be viewed as a 3D version of the 2D honeycomb and the new magnetic compound [(C2H5)3NH]2Cu2(C2O4)3 provides a rare example. Honeycomb type lattices are expected to support spin liquid ground states when favourable patterns of spin interactions are present. This can happen when spin orbit coupling is strong (as in the Kitaev model) or when next-nearest-neighbour interactions are a significant fraction of the nearest neighbour interactions (J2/J1~0.2-0.4), as appears to be the case here. Following Jahn-Teller distortion around the Cu sites, a 2D magnetic lattice emerges that is honeycomb-like. Various measurements show gapless 2D spin liquid character, including muon data down to 60 mK. Distinct sub-phases found within the spin liquid require taking further muon data in a set of LF scans between 50 mK and 15 K. This will allow a thorough test against theory.