Could you get the new Ero to use the same wifi credentials als the old one?

Edit: you’ve deleted the old network from the system.

I’d connect one of the speakers by cable to your router and do the set up from there.

You’ve followed the instructions in the new router - installation instructions FAQ?

What I’d likely do is wire one Sonos device to the root device of the new router with an Ethernet cable, to get the system up, while working through the rest. 

Yes, to both questions. and I get an error stating that it cannot connect. I may need to try the Ethernet option 

Do you have the eero WiFi options set to support the Sonos requirements?

https://support.sonos.com/en-us/article/sonos-system-requirements

https://support.sonos.com/en-us/article/supported-wifi-modes-and-security-standards-for-sonos-products

Have the same issue. Called SONOS and after 45 minutes, couldn't fix. 

I can connect the beam but not the mini sub. 

I've since used my booster and plugged in direct with ethernet to beam and sub which works however would like to use the WiFi. 

I'm on new Vodafone Ultrahub 6E

I would perhaps check that Vodafone router does not have ‘AP isolation’ enabled on its WiFi network connections as I’ve seen that mentioned in the past online for a number of Vodafone products.