CeX is selling it for £15 and pays £10 voucher for the game, so hopefully no loss here! 26 in stock as I checked but Amazon is also selling it for 3p more in case if you miss this one.
Ace Combat Assault Horizon Legacy + is a revamped version of Ace Combat Assault Horizon Legacy released on 3DS, but specifically adapted to the New 3DS. It combines Ace Combat series strengths with the specific features of the New 3DS. The title even goes further by taking advantage of a deep collaboration with Nintendo.