Well just got back after trying. No go.
Asked him to power down all his gear before I set off, took about an hour to get there so the cable modem should have had plenty of time to release the mac from his router.
Tried a patch and a cross over network cable from the infintiy port to the cable router, just an amber light and no internet connectivity. Also tried a few factory resets in between and disabling DHCP - not that that was ever going to work since the cable modem wasn't in the mood for assigning IP addresses... being a modem...
Also tried changing the HH3's network address from 192.168.1.254 to 192.168.1.11 to match the cable router and same result.
Anyway put every thing back the way it was and powered it all off, told him to wait 40mins before switching it all back on. Glanced back at the cable modem and it was still on! He switched the wrong [censored] thing off so there's a chance it never released the mac address and that might have been all it was!
In anycase i'd already told him to go buy a netgear or something and I can't be bothered with trying again lol.
Edited by deleted (Sat 04-Jun-11 13:37:25)