No they certainly do not have a copyright on the flags They cannot stop anyone producing a very very close imitation of their drawings But following the blazonemblazon argumentation they may have a copyright on their particular rendering of a flag even if the flagblazon is PD I think the issue is similar to maps the geodata is PD as bare facts well for the time being at least but a particular map drawn from that geodata is copyrighted We may draw our own maps but we cannot copy someone elses copyrighted map  Besides I take the liberty to not support either side here As I wrote above I did not tackle the issue until now and I dont feel I know enough about the issue to give an opinion with confidence I just think that it is well possible that they do have a copyright on their images  Except maybe in the case of very simple designs three differently colored stripes for instance where indeed a no originality claim might be valid But for more complex flags that argument breaks down AFAIK identical blazons have been rendered quite differently throughout history eg with animals shown in a more classical or a more modern style Take for instance ImageKent Flaggif The blazon is Gules a Horse forcene Argent Now look at the COA shown there at our flag and at the renderings on the website of the Kent County Council I think they all comply with that blazon but are all different and IMO show enough creativity and originality to be individual copyrightable works