Just an update on this. I looked at several other threads and DNS leak seems to be a known issue with VPN. To summarize the problem I was trying to solve was using PBR ensure all traffic for a specific IP address is routed over the WireGuard VPN tunnel. The issue I was seeing is traffic was going through the VPN (when I added the routing policy for the ip address in PBR LUCI interface) however it was not getting the DNS servers specified on the WireGuard interface instead it was using the DNS server on the LAN interface (which defauluts tto the ethernet IP of the routers LAN interface). The only way to force the IP client to use the DNS servers of the WireGuard VPN provider was to use DCHP Option 6 tag (see example below )
config host
option name 'LAPTOP-PH3AFI'
option ip '192.168.1.161'
option mac '88:D6:2E:C4:F8:9C'
# option tag 'tag1'
#config tag 'tag1'
# list dhcp option '6,162.252.172.57,149.154.159.92'