Charlie
The copper strap you are fitting to the keel bolt. You may find a green and yellow wire attached to the engine/C drive which is currently doing nothing. This should be attached to the top end of the copper strap. If it is missing put a new wire there. This connects the engine C drive to the anodes on the rudder. You’ll see the same yellow green wire on your toilet valve through hulls etc and from your rudder quarantine. There is a network of these wires leading back to the rudder.
I haven’t seen a bonding layout, but I know where all these wires are that are part of that on my Santorin.

Have fun with the bilge!

Ian