OK, I am thinking a little differently. I had an instance a week or two ago where Unbound decided to go gaga, not for any reason I could see, it just did, it's not happened before. Now, I'm not sure CARP would pick this up, as the interfaces were still responding. I also have Home Assistant, that now watches the Unbound service, it also watches the gateways, and flags a warning etc. I'm going to use this flag to close one of the LAN ports on the switch so the primary router will be seen as down by the Proxmox instance and promote itself. This is the theory anyway, in practice we'll see what happens.
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