You could check out Latitudes.
Latitudes.org
Our Child Health and Autism forums here are quite slow lately unfortunately.
Often you would find special diet information in those types of forums.
I did a quick search in there and didn't find anything specific to Gut And Psychology Syndrome.
You could try a Full Forum Search.
http://neurotalk.psychcentral.com/search.php
I just did one but so far could only find mention in one post in Epilepsy Forum where someone was discussing ketogenic diet and similar.
Epilepsy Forum
Edited to add: I just found one post by searching for "Campbell-McBride" (author/founder of the diet book)
That is in the Peripheral Neuropathy Forum and unfortunately the author of the post
only ever posted once.
Here is that link though -
Post 9 - : Reversal or improvment of your PN!! (success story's)
Had another thought. I tried searching for
"
Specific Carbohydrate Diet"
and there were quite a number of posts.
Do you own the GAPS book??