It's working!!!
I went out to the van and moved the cables so that the inverter and battery connections are on opposite sides of the shunt. I followed Greg's (Scalf77) advice and placed the inverter connection on the same side of the shunt where the vehicle ground is connected.
I had to ensure that the blue and orange wires were on the correct sides of the shunt with the blue wire connected to the battery side.
It took less than 10 minutes to make the changes and when I powered it up and went to the DC amps meter on the remote panel I could immediately see the amp readings changing as I turned on things in the van. I discovered that if I turn on all the lights, the fridge, the vent fan and start up the Espar D5 hydronic Comfort Hot system, I am drawing about 21.5 amps. Nice to know.
I also started up the van and engaged the high idle to charge the batteries via the second alternator. I could immediately see that the alternator was pushing almost 8 amps to the battery bank. Great to finally see that.
I finally went to the SOC meter reading and watched as the SOC went from 100% to 98% as I continued to draw from the batteries with all the DC loads turned on in the van. Everything seems to be working fine now with the wiring changes to the shunt.
Thanks to everyone who contributed to this thread. I'm now documenting the changes I made to send to Sportsmobile North. Hopefully, that may save someone else from having the same issue.