I have a DVD+R full of data, its not a film. What do I need to do to copy this to DVD-R discs, or is it simply a case of buying some +R's
Most dvd burning programs have a DVD copy feature where you put the first dvd in the drive, it reads the data files to your hard drive, and then it spits out the disk and asks you to put in the blank disk, then it burns it. Or you can do it yourself manually. It doesn't matter whether one disk is minus and the other plus, or both are the same. If your burner is dual format (most are) you can buy either kind of blanks and just use them.
If the recording drive supports both formats, + and -, all you need to do is make a copy. Nowadays most burners do.