It appears as if the driver that we have in the build disk is not a custom one and is actually from one of the RM Driver Updates.
Unfortunately I don't have enough time right now to figure out exactly which of the Intel ones listed in the build was used but these are the ones that I've got listed for the build disk right now if you want to check against yours:
RM PC 310 WinPE LAN Driver - 184.108.40.206
Intel Pro 1000 Ethernet NIC [RM Ecoquiet 965][Vista] - 220.127.116.11
Intel 82567LM Gigabit Network Adapter [DQ45CB][Vista] - 10.3.39.0
RM Ecoquiet 300 LAN Vista Driver - 18.104.22.168
RM Expert 300 LAN Vista Driver - 22.214.171.124
Hope that gives you some pointers.
Thank you for your time.
I have all of those (I have all driver packs installed) and to make sure I have added them all to the build disk and regenerating it again to test.
Well, I dont want to count my chickens etc etc but one of those was the one, it got an ip when I booted from the new build disk and is working, I know it could still fail after this, but it's a step forward, thank you.
With the above drivers from ajs and the latest from Intel, this now builds. This has taken me the longest to do, but glad its now working. Time to place the order.