In my update file I keep the AVG update control file AVG6info and the latest AVG update file currently d602vmhf all update files pre 19/5/2003 have been deleted, my Grisoft folder is currently 11Mb in size. Think about it, if you needed 33mb of dat files, the program download from grisoft would be at least that big, but it isn't.
I don't know what it was, and I didn't delete it myself, but when I looked for it to delete it, it had vanished. I have view hidden and system files turned on too. Mysterious, maybe a temporary file created during the scanning process that got left because I did a manual reboot during a virus check. Who knows, but it doesn't seem to have any adverse effects, not being there. AVG still runs and updates correctly.