Thanks Nick,
I get the Gist (though not all the abbreviations, IIRC? CDC? YVMV? - sorry my dim!). My issue with VH is that they do not make this clear at the point of booking. By their own admission the customer only learns their ticket classification when they receive the tickets (which can only be downloaded some weeks later - at least in my case).
As for the Limo, this is the wording used by Virgin Airlines, though I gather now that it is either a people carrier, a saloon or some such.