Thanks guys. When I have time (and the nerve) I'll try removing the starter version of 2010 from the laptop and see how that goes. I notice that the unsuccessful removal 'fix' provided above should only be necessary if there's been a problem with the installation of the starter version. Since it was factory installed and hasn't been used I'd like to think it's OK and therefore that the fix won't be required.
I'm just a bit worried because I don't want to get left with a machine which hasn't got Office 2010 starter but won't let me install the 2007 version.