Thanks guys. I get that the config it retrieves depends on what you have configured, my question was more around how it works before this. For example, what VLAN does the Meraki switch by default try and learn an IP address on (via DHCP)? I'm guessing VLAN 1.
In that case, if my Meraki switch is getting an IP address from my management VLAN (say 100), I would need to have the switchport on the Cisco neighbor set as a trunk with the native VLAN set to VLAN 100. This way, the Meraki would pull an IP address from the VLAN 100 subnet using its native VLAN 1......
My background is routing and switching, so trying to understand the mechanics around the initial registration of the switch with the dashboard....