I accidentally opened my email instead of Word so decided to clear my browser caches and reboot and the Wi-Fi is working again now... yaaaaay! I've restarted the deep virus scan and I'm hoping it'll be a bit quicker now that all those small files are no longer in my browsers. Hopefully the Fitbit app will be able to sync with my tracker now that I've got my Wi-Fi connection back.
Needed to hit F5 for yesterday and today in the app then it updated itself seemingly easily, so it seems to need a Wi-Fi connection rather than a wired connection for some reason. Everything is up to date again now though, so just gotta be patient with the deep scan again now.