Third attempt - BuddyPress 1.5.1. linking all wrong!!!

I've tried buddypress forum's twice with no response and posting here for a third time HOPING for some help can be received.

I had a WP multi-user site, http://retrofitdiaries.org, that has run over a year using Buddypress and Network theme WORKING FINE 'til yesterday until updating Buddypress to the current version 1.5.1.

In fact I received much help from WPMUDEV in implementing an early version of Network - and IT WORKED FINE.

Now, all Buddypress features do work yet don't appear to due to incorrect Buddypress linking (all except community streams on the top level site are incorrect).

I've done nothing unusual, tried turning off all other plug-ins to no effect. I don't see why other people are not finding that Buddypress isn't totally failing in this version.

The issue is that all references go to non-existing urls with an unnecessary blogname inserted before the site title.

There are so few options with Buddypress and I've not changed any - why is this happening? Pleas can this be addressed....