Thanks all...
It's not stunning, but with the feedback I'm encouraged that it should work pretty effectively.
I went though so many design options working on this logo, with no guidance from the client. In the end he reverted to an early (and quite plain) option and then we tweaked it a little.
It is about small adjustments at this stage since client is happy with it. I think sorting out consistent spacing between the shapes will help. The colours ARE very predictable, but anyway.