Heya all,

gee, I hope someone can help me, I spent over an hour on chat with TPG support but they couldn't solve my issue either; and I think its going to be a "you're a moron" moment for one of you. I should add me being the moron, not support. They were as helpful as they could be. I'm in AU if that helps. 
So, brand new M5 mesh system. Existing router/modem kept crapping out on the wifi. Have placed the old device (Huawei 659) into bridge mode, and set up the wifi network. It could not have gone cleaner. Great integration. All of the wireless devices in the house were up and running in no time, with solid DL and UL speeds across the board. 

But ... I cannot for the life of me get my desktop running. The ethernet is plugged directly into the main Deco, which itself is wired into the Huawei on LAN1. I changed adapter settings to automatically configure DHCP and DNS, and I can see from ipconfig that the new network has updated the desktop IP. I can also ping the Deco, but cannot ping Google DNS, for example. ipconfig also tells me that the default gateway has been set, and that it is the same as the wireless devices in the house. 

Is this perhaps a VLAN issue, or .... ? 

I have two other wired devices (Philips Hue and a Raspberry Pi running AirPlay), but both of them only require the internal network, and they work well (very well, I might add). 

Argh... The frustration is setting in ...