Thanks for the reply - think I get it now...........

Each set is comprised of a 'complete' backup plus however main daily incremental 'sets' ?
I presume this is so that you can put more than one 'complete' backup + 'incrementals' on a disk/share ?
My suggested wording for the boxes would be something along the lines of :
Complete back up (Number of rotating backup sets)
Number of incremental backups (Daily backups in each set)
We only have the office open Monday - Thursday and they are used to changing the disk on Thursday evening before they go home so I guess I run the main backup Thursday evening with increments to follow.
I would change disks with each set so I guess one set with daily sets at 7 ?