Well, since i cleared my log that painful Nokia ringtone hasn't appeared, until today!!
So i cleared my log again (i've left the setting on 30 days)and hey presto the Nokia ringtone vanishes thank god. Today is the 30th day since my last call log clear out-weird it plays up now! Not sure whether it's a rolling 30 days or after 30 days from the first log it clears the last 30 days. (If you know what i mean)
Not to worry, i shall look forward to the Nokia tone in 30 days time-not!