OK confusion resolved, by describing the conclusion informally as necessarily true and then equating the term via the link to the definition of an analytic proposition the absurdity arises. Seems obvious now should've recognised it myself, thanks for your patience and answers.

Thanks for the reply, my confusion arose after reading the following on the deductive reasoning page of wikipedia.
"Deductive reasoning goes in the same direction as that of the conditionals, and links premises with conclusions. If all premises are true, the terms are clear, and the rules of deductive logic are followed, then the conclusion reached is necessarily true".
The italicised part of the quote is a link which takes you to the logical truth page where it says,
"A logical truth is a statement which is true, and remains true under all reinterpretations of its components other than its logical constants. It is a type of analytic statement".
So it sounds like whats being said is a valid argument with true premises (ie a sound argument)s conclusion is necessarily true and that necessarily true propositions are analytic propositions.
I understand if the argument is valid then it is "truth preserving" ie true premises will always give true conclusions, I guess its just the use of the term "necessarily true" especially if we are to insist (correctly) only analytic propositions are necessarily true.

All Greeks wear sandals
Socrates is a Greek
Therefore Socrates wears sandals.
Clearly the subject term Greek does not contain in its concept the predicate term "wears sandals" nor does the subject term Socrates contain either the predicate term "is Greek" or "wears sandals".
The above argument is valid and if its premises were true its conclusion would be necessarily true. It is the case premise 1 is false but that just proves premise 1 is a synthetic proposition if it were analytic it could not be false.