Children's publication in decline (5)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Another one I don’t understand. How is “Beano” in decline? I know beano means a party, besides the comic (of which I was an avid fan from childhood through adolescence – yes until about 33) Is it asking us to read it as “BE A NO” i.e. decline something offered? If so that feels a stretch to me.