L2TP and IPSec with EdgeOS 1.9.0

I am setting up a new L2TP/IPSec VPN on my ERX SFP running 1.9.0, and it doesn't seem to be pushing a default route to clients. When I connect using my laptop, for example, my laptop gets an IP in the range I specified, but the Default Gateway field is blank.

If I connect to VPN, I can access things on the LAN using IPs but can't access the Internet. 192.168.4.1 is my router's LAN IP (switch0).

Config below - can anyone shed some light please? 

david@RoutyMcRouterson# show vpn
 ipsec {
     auto-firewall-nat-exclude enable
 }
 l2tp {
     remote-access {
         authentication {
             local-users {
                 username xxx{
                     password xxxxx
                 }
             }
             mode local
         }
         client-ip-pool {
             start 192.168.78.101
             stop 192.168.78.105
         }
         dhcp-interface eth0
         dns-servers {
             server-1 192.168.4.1
         }
         ipsec-settings {
             authentication {
                 mode pre-shared-secret
                 pre-shared-secret xxx
             }
             ike-lifetime 3600
         }
         mtu 1492
     }
 }