the version of Screaming Secrets from Zoology IS the Peel Session, as a matter of fact most of the rare songs on Zoology are Peel sessions or BBC sessions.
Are you sure? According to the sleevenotes they're demoes, albeit pretty similar-sounding to the Peel vershs. For Screaming Secrets on Zoology it sez "recorded at Bear Shank Lodge on the Stiff Mobile."