Forwarding VOIP packets back over VPN

[mns3476]

I am trying to set up a VOIP desk phone to work over a VPN for a remote worker, I have a nano travel router that has built-in OpenVPN client (& FW+NAT) and provides a remote LAN of 192.168.8.

The VOIP phone is on this remote LAN (192.168.8.221) and can connect to the phone exchange with control data over the VPN, as it originates from the phone.

But the voice data originates from the exchange and tries to send RTP packets to 8.221:29100, this has no route across the VPN.

VOIP Phone Exchange 192.168.1.50
 LAN 192.168.1.0/24
PFSense LAN 192.168.1.1

PFsense OpenVPN 192.168.50.1
 VPN 192.168.50.0/24
VPN Client Router - 192.168.50.3

 Remote LAN 192.168.8.0/24
VOIP Phone: 192.168.8.221

I have tried to setup a interface for OpenVPN & Gateway, a static route for 8.221, and incoming NAT for 8.221 to redirect to 50.3 the VPN router which has a port forward to 8.221 on the lan. This didn't work & couldn't see the 1.50 source packets on the VPN interface.

I need to start from scratch really, is this the right/best way to do it?