Did you upgrade Numbers? That sounds like a Numbers issue and not a Mavericks one. If it is a new version of Numbers, downgrading to SL won't work since once upgrades are made available on the App Store, you can't get older versions (unless you've got an old copy archived somewhere).
Dave - many thanks indeed - my wife is now Happy !!!!!
Great reply - a simple thing I know but difficult if you were born in 1941.