Distribution of elliptical distance (cf Sect. 4.4) measured in the source plane between Lyman-α emission centroids and the ellipse formed by the UV emission distribution (using r_90,UV as radius). The grey distribution represents all the LLAMAS galaxies and the black hatched only the galaxies with a spatial offset probability higher than 95%. The vertical dotted line represents the separation between internal and external spatial offsets (Δ_ell = 2).