OK - finally got it working…
First - I had no "generate_policy" command
Then - I had various firewall issues on the pfSense end (it would make sense to have some indication that the IPsec connection will be pointless until explicitly openned)
Then - I had firewall issues on the other end
Then - I had routing issues on the other end (masquerading got done before IPsec got a look in)
My head hurts.
I'm going for a lie down.