ED visa to marriage extension NOT possible

Just thought Id inform everyone that I went to CW today to try and do an extension based on marriage with a non immigrant ED visa as Id read here that some people had apparently been able to do this, anyway I was told straight away by the officer that this most definitely is NOT possible and even when I said its a non immigrant visa and brought out last August's police announcement she was quite adamant its not possible and must be a Non 'O' one. I was sceptical that it would have ever been possible but thought it would be worth a shot but looks like a trip to Laos for me, Im putting this up here to warn people who are searching for this same topic just like I did anyway!