2 routers in the chain, vodafone and google wifi is port forward the answer ?

[broadview]

so..... vofaone router and a google mesh kit ( 3 pucks)

I had the vodafone router 192.168.1.1 which currently forwards to the NAS 192.168.1.99

but now as I introduce the google mesh now I have the voda router

(which cant be put into bridge mode, not great vodafone ) which then plugs into the 3 x google mesh which links via LAN to the rest of the house via ethernet on address 192.168.86.x

so the whole house is on 192.168.86.x as that is googles ip config

I assume I need to forward from the vodafone to the google ? if so how do I set it up rules to forward from 

Vodafone router to the gogole mesh & google mesh to the NAS ?

vodafone wifi is off as isnt needed

[CrimsonLiar]

In this case, you don't!

Port forwarding rules apply to data coming in over the WAN/xDSL connection.  There is no means on the Vodafone routers to apply the needed IP table rules to the LAN ports on the router.

If your other devices are connected to the Google Mesh devices, then you'll need to connect the NAS to that network too and not to the VF router.  *Still leaving you double NATted, which can cause multiple other issues!