occasionally my dashboard states that I don't
That's frequent behaviour. Its annoying that giffgaff doesn't fix it, but it's very common if you've been logged in to the forums for a while (about 20 minutes seems to be sufficient).
Sometimes, logging out and logging back in will fix it. If it doesn't, then:
close the browser
make sure no other browser windows are open
open a new browser and log in
go to the dashboard soon after, so that the dashboard server doesn't have long enough to time out on you.
Yes, its a BUG which has been around for years and needs fixing -- but giffgaff seems to think it's a very low priority.