Draytek Vigor 130 > Fritzbox 7390 - different subnets - need help!

I've just picked up a used vigor 130 so that I can utilise my (being delivered) unifi USG as the fritzbox doesn't do bridge mode.

I've got the DV130 setup as 192.168.0.1 with DHCP off and my fritzbox is running on 192.168.1.1 (also with DHCP off); I've got a whole bunch of static IPs assigned to various things including my domain controllers so shifting things up by 1 is a no go and I don't actually need to see the vigor on the lan in general - makes it neater for fibre install later too.

What I have done so far is:

Assign a static route on the DV130 to 192.168.1.0 with netmask of 255.255.255.0 and a default gateway of 192.168.0.1

Assign a static route on the 7390 to 192.168.0.0. with netmask of 255.255.255.0 and a default gateway of 192.168.1.1

I figured this would be sufficient to be able to route clients from my LAN to the DV130 but it doesn't want to work.

Is someone able to point out where I am going wrong? I've never played with subnets before but its always a good time to learn right?!?! Be good to get this sorted before my USG arrives so I can just plug and play!

Thanks,

Chris