Thanks everyone. Not much room left for reindeer now:
I
think that the secret to getting multiple flags is finding links that don't repeat a country/language combination you've already used. So if your HON flag came via a URL that includes "UK_en" you can't use that combination again. Ones that worked for me included "CH_de", "DE_de" and DE_en" (and then
NewbieRunner's "UK_en" HON link to complete the set).
Just changing the country/language bit won't work: you need to follow a full working link, all of which are now to be found above.