I have searched for a Queen (the band) flag to no avail. I have seen them flying at shows and such. Just a flag with a Queen logo on it that is all.
Try here. They seem to ship internationally but it seems you can select an image and have it printed on a small (10x15cm) flag with pole and base for 10 pounds ($17 or so?)
Umbrellas 25 pounds, bath towels (narrow image) 15 pounds. Googled Queen "fan club" and followed whatever merchandise links I could find.
Here’s another shop, no flags I could find but a lot of other cool stuff. Hope This Helps.