We examine the family of discrete Painlevé equations which were introduced under the qualifier of “alternate”. We show that there exists a transformation between the two canonical forms of these equations, and we proceed to link these forms to the contiguity relations of the continuous $\mathrm P_{\rm VI}$. We describe the full degeneration cascade of this contiguity, obtaining all related discrete Painlevé equations (among which, one which has never been derived before) as well as mappings which are solvable by linearisation.