This has just been bugging me. I have to agree with me and with a: 'enlargement' just sounds wrong (though amusing). To my ears also, any larger abstract context such as a political alliance or community would use only 'expansion'; in contrast, 'enlargement' does indeed imply an actual concrete object. A body part, absolutely; or, say, a print of a photograph.
And in fact, a web search suggests that in the EU context, 'expansion' is the term that's used around the world (by the major broadcast networks listed above, just for starters), whereas 'enlargement' is chiefly European. The EU can certainly use it itself if it wants to, but they can't legislate world usage. Like Peter <us>, I think it's still too early to predict how much Euro-English will catch on elsewhere (though I suspect it will be a lot). For the present, anyway, since 'enlargement' is so awkward as to sound incorrect for many native speakers, especially outside the EU, it surely should not be the only option listed in LEO.