Buddypress /register/ page disappears/replaced

When I install your plugin it works perfectly – except, my existing buddypress registration and login (with custom signup questions) is now replaced by what looks like a standard WP Login/Register fields.

Q: how can I disable that and keep my original Login/Register signup page/fields?

(I cannot see any shortcodes in my exiating BuddyPress register page – it’s blank)

The page I need help with: [log in to see the link]