delsdog: if it's worked this long then it probably won't change - at least that's my conclusion after a lot of Googling trying to troubleshoot one! They either work fine, or they're a problem from new.
My first BEFSR41 is somewhere in Royal Mail's hands, winging (or crawling) it's way back to Amazon. I'm hoping the replacement will work, but...
Anyway, I'm one of those ppl for whom it works perfectly for a time (in my case, about 10 minutes), but then refuses to display any webpages, including the router's set-up pages. But I could still email, and ping both router and any site I cared to try.
For the record, linksys uk took just over a week to reply to my email, to then say "very starnge (sic), update the firmware"
Fortunately their phone tech help was slightly more use, although I struggled to understand the accent of the person, they did confirm I'd tried everything & should return the router.