Thanks Julie, pretty much what I have been doing. After any change the file gets saved as a main file, then I statr a sub file (same programme, different name) to see where it gets me. I have never been a fan of autosave, but our IT dept tend to use it as a crutch every time there is a problem. No change there

You're welcome. Develop the CTRL+S "twitch" and save early and often.