Network Theme Buddypress 1.7.1 & bbPress 2.3.2 Forum Search not functional

I've just upgraded to Buddypress 1.7.1 & installed bbPress 2.3.2 as the previous inbuilt buddypress group forums model is now legacy.

I have found that the Forum Search in the Network Theme is not functional on the main page (top left) where there is a built in search feature for searching blogs, members, groups & forums.

Can you advise?

Mark m.