Twas very strange, the bookmarks/favourites in IE were imported from FF as were the ones in iron, in the end I logged in using IE, copied the URL and pasted it into FF and lo and behold I'm logged into hot mail, same with iron. Whilst I accept that a book mark can become corrupt the fact they were the same in FF and Iron rather rules that out so I have to assume that the URL was changed and that IE was automatically updated. (but I'm not convinced)
Migrate to Gmail. It is easy.
I do have a G Mail account mainly because one site I wanted to register at insisted it would only accept G Mail addresses, I don't trust Google not to use things for their own ends.