Check out this site, fussy-eaters.com. It’s broadly UK-based, and it’s got message boards for adults and for parents of fussy eating children. I also think the name fits better into the British idiom than “picky eating” does. I wish I’d had the courage of my culture to use “fussy” not “picky”.
Anyway, it’s a great forum and community – check it out, if you haven’t done so already.