So is it Britain or England? I'ts not 'rocket science' guys.
As the other guy said, Britain or England are both correct, since England is a part of Britain and despite their position quite some distance from the mainland, the Scilly Isles are still considered part of England.
As a nationalistic Scot, I dislike when "England" and "Britain" are used interchangeably, and the headline/summary discrepancy does smack of that being the reason- however, since it was still technically correct I wasn't going to make a deal of it until you made that comment.
(You can stop reading here if you don't want a confusingly-detailed breakdown of the various terms. Just at least do me a favour as long as I have to remain technically British and don't assume "English" and "British" are synonyms! )
FWIW, if one wants to start nitpicking, the term "Britain" on its own isn't really well-enough defined in modern usage to argue over- beyond the fact it definitely *isn't* synonymous with "England". Generally "Britain" tends to be used even by people here as synonymous with the political state of the United Kingdom (i.e. the "United Kingdom of Great Britain and Northern Ireland"). "Great Britain" is the geographic term for the main island including Scotland, England and Wales, but not Northern Ireland, hence the full name of the UK. Meanwhile, the "British Isles"- a geographic term- includes the island of Ireland (part of which is of course an entirely independent country), along with some others such as the Isle of Man and the aforementioned Scilly Isles. (Some people in the Irish Republic dislike the term "British Isles", which is understandable given the use of "British" above).
What's really going to bake your noodle is that whereas the Scilly Isles are considered part of England, the Isle of Man, despite being a British crown dependency roughly the same distance from the mainland, isn't even technically a part of the United Kingdom itself...
Actually, now that I've looked into it, the Channel Islands (i.e. Guernsey and Jersey) are also considered a part of the "British Isles"- a nominally geographic term- despite the fact they're far closer to- and more obviously associated with- France. One might suspect they were only counted as part of the "British Isles" for political reasons, since they're British crown dependencies, albeit not a part of the UK itself (like the Isle of Man).