Hi All - for anyone reading this thread - I have figured out this problem myself - basically the "Delete List" button at the bottom right will give you the error code "invalid data", the "Delete List" button top right will delete your list - hey this is a great forum - list your problem - bang your head up against the wall for 24 hours and solve the issue yourself - HELLLOOOO is anyone OUTTTTT THERE.
Peter Davies
London UK