Back in June 1989, Potpurri featured Mint & Boxed, a British-based antique-toy emporium that issues a semi-annual catalogue crammed with vintage playthings. Mint & Boxed has recently opened a Manhattan gallery at 1124 Madison Avenue, New York 10028. So toyland is even closer at hand. The company still publishes a catalogue ($34 for two issues), but that’s like reading about Santa’s workshop instead of visiting it. It’s the ultimate old-fashioned Christmas at anything but old-fashioned prices.