Nearly 12,000 posts!?! wow!
Earlier today I discovered that when utorrent crashes my internet, instead of running downstairs to restart the router I could just unplug the homeplug and plug it in again and it would be back up in seconds (certainly saves my legs!). That suggested that the problem was the homeplug, and then tech support also said that so I gues that's what the problem is, so I'm halfway to solving it. Thanks for confirming my suspicions about the 85mbps homeplugs.
200mbps is the biggest type of homeplug, right? A quick google has revealed that the throughput on the zyxel 200mbps system is about 100mbps - would that be enough?