It turned out I hadn’t deleted all the old blogs. I kept an old LJ one for reading friends’ journals and hadn’t realised I could import those entries too. Then I double-checked the blogger accounts and found that I had just archived one of them rather than delete it.
So I have most of the entries between March 2004 to March 2009 – I got rid of some posts which I no longer wanted to keep but the rest are there.
The only things I’ve lost are the posts from a knitting-only blog I had in early 2009, and the very few posts I made on the main blog in 2009/early 2010 and to be honest… I figure I would have deleted most of them anyway.