I have just noticed this forum section and thought it worth mentioning the fantastic customer service I recieved from Billion UK.
Having purchased a second hand router I decided to upgrade the frimware without first properly reading the formware upgrade instructions and managed to turn my nice new purchase into a 'brick'.
I found the technical suport section on the Billion UK webste and submitted a support request, I admitted that the router was second hand and I had no idea if it might still be in waranty. Within a day I got a reply with attached 'rescue' software that required me to connect the (supplied with my router) serial cable to a PC to reset the thing properly. The only difficulty was finding a PC with a serial port (had to take my router into work) but it worked and saved my 7402NX from landfill. I later updated the firmware again but followed the instructions, has been an excellent router since.
On a slightly less positive note, why do Billion UK firmware updates seem to lag so far behind Billion Australia, still waiting for IPV6 firmware which OZ has had for months.