WP-Activity caused the custom post-types and taxonomies used by Gorilla Themes Smooth Pro Real Estate theme to break.
All theme custom content types return 404 error when requested or clicked from front end links.
Editing and creating new content using the custom types not affected, but they cannot be previewed or viewed at all.
De-activating WP-activity restored the theme custom types immediately.
This may affect other Gorilla Themes - they seem to use a lot of shared code.
It's more likely bugs with the theme code than the plugin - Gorilla custom content types are poorly hooked into WordPress - they really need to update their code and use compliant standards. Pity - Gorilla make great looking themes with super functions
Published this notice in case other Gorilla theme users have problems.