I have moved the experiment to the WORK PC - windows 7/8, not xp and not vista - because it has a DVD drive of its own. do I can try on both my freecom drive and the one built into the Lenovo laptop I use for work. Here are the results
Freecom DVD writer - using drag and drop - does not recognise blank disc, spits out DVD demanding a blank one
Built-in DVD writer - works fine using drag and drop
Would seem to be an issue with the freecom drive but it should work with DVD- r as it says on the back of it.