Thanks for your reply.
My hard drive is only 55% used and 45% free.
I run Defraggler and CC Cleaner once a week and noticed my system restore files were being deleted. So I created a new restore point and ran cc Cleaner and the restore point remained. Then I ran Defraggler and the restore point was removed and missing. So therefore it must be Defraggler removing the restore points. Really not sure why and I definitely do not want the restore points removed.