I ran CCleaner v5.05.5176 (64 bit) on my windows 7 (home premium sp1) laptop to wipe free disk space and chose complex 7 pass.
I then ran Recuvva and although there were only a few files in normal scan, when I ran a deep scan there were a large number of fully recoverable files, in some cases the filenames had been serialised as numbers and original location lost but many files were fully named and fully recoverable.
I have since used defrag and a second pass with CCleaner and still those files remain.
Advice welcome