Our recent µSR measurements on a polycrystalline sample of Ru7B3 has shown that this material is an excellent example of broken time reversal symmetry on entering the superconducting state and also probably has a square vortex lattice at low temperatures. A question exists on the importance of the role of the electron phonon interaction in determining the mixing of the s and non-s components of the superconducting state. We propose to examine a similar compound to Ru7B3 but with rather different masses, La7Ni3, to observe how the superfluid density and vortex lattice morphology change with modifications of the vibrational properties.