I currently have a TPlink archer VR1600V  as my primary router connected to my nbn modem. The VR1600v is being used for VOIP however wasnt happy with parent control features. It is currently configured as a DHCP server and 192.168.1.1. Wifi networks on this modem are disabled (including guest wifi).

I bought the TPlink C4000 Archer and created a lan - wan network (lan of primary router_ to wan of the C4000- secondary router) after playing around with it. The sec router also has dhcp server enabled. Wifi for 2.4 and 5ghz are enabled on this router only. This is currently working and allowing me to use parent control features for all wifi connections to the c4000. 

The problem is that obviously a lan to wan router network means i have two seperate networks and main pc on primary router network cant communicate with printer or devices on which are connected tothe secondary router / network.

I tried connecting the c4000 to the vr1600v via a lan to lan connection, disabling dhcp and assigning a static ip address to the secondary router within the primary router pool of ip addresses, however when i do this the parent control features on the c4000 (Sec router) are not available. The manual says that when the c4000 is setup as an access point parent control, qos etc are not available.

Is there any way i can configure the c4000 manually using a lan to lan connection so i can communicate with all devices via a common network and still have the c4000 manage its wifi connections with parent control QoS ? 

Really appreciate the help.