@JTT,
JTT wrote:
Perhaps the indefinite article 'a' is left understood. Am I correct in assuming that they are not the only one?
'We're a Britain's In Bloom borough'
Well, the apostrophe would be an error, given that the competition is "Britain In Bloom". Each year there are plenty of finalists. In each of these categories there are Gold, Silver Gilt, Silver and Bronze winners, plus a Champion Of Champions: Small Village, Village, Large Village, Small Town, Town, Large Town, Small City, City, Large City, Urban Community, Small Coastal (electoral roll up to 12K), Large Coastal (electoral roll over 12K)