Many thanks for your post. I am now getting confused, I am afraid. The reason that I got my base backup programme was that it did 'normal' and differential backups, but having now checked - fololowing your post - I do not think it does incremental backups.
I haven't used these for a long time and I thought that these were the differences between each of them and that each backup - either the base or an incremental - had to be perfect, otherwise you lost all backup information from the first 'imperfect' one through all the rest. As there was thus a considerable risk with these it was better not to use incremental backups as such. Or are you suggesting otherwise? And if so what programme(s) would you think would be worth checking out?