Thank you all for your replies. I looked at the Anderson PowerPoles and they look very good but they would either have to hang down underneath the cross-members or I would have to drill larger clearance holes through them.
I tested a barrier strip inserted into a temporary bus run and measured the end voltage to ensure that there would be no drop. These have the advantage of requiring only a small clearance hole for the wires to pass trough end cross-members, and to disconnect it is simply a manner of undoing a screw and pulling the wire. Simple, inexpensive and neat in terms of appearance.
The barrier strips can be cut to length depending on how many bus runs are going across the joint between sections.
Tim