Thanks, I thought the fire was probably IR interference. I guess I just have to not light the fire if I want to use the Wii - it's a bit inconvinient but I can live with it.
As for the other problems, I thought the games refusing to load and the network stuff might just be because the firmware/OS was new and buggy or the network busy but if other people aren't experiencing these problems perhaps my Wii is just broken. That would be a pain - I don't particularly want to part with it while they fix it, especially over christmas.
BTW my firmware version is 2.0E (it's displayed at the top of the Wii settings menu), does anyone have a version different to this (more recent?)