Many formulations comprise distinct chemical species that exhibit antagonistic or synergistic interactions that result in unpredictable behaviour. Previous work from our group has focused on how surfactants modulate the interactions between lattices of varying hydrophobicity with hydrophobically modified neutral water soluble polymers. Our "deconstructionist" strategy was to first understand the binary interactions (e.g. polymer/surfactant and polymer/particle) before reassembling the ternary mixture. SANS - using contrast variation - was a key element to this success. Here, we wish to continue this approach, turning our attention to a somewhat more challenging situation, ionic species. We wish to explore the interaction of anionic particles with cationic polymers, whose charge density is controlled both through the degree of cationic modification and the presence of anionic surfactants.