I wet the shirt. Poured lots of ariel actilift powder on it. Rubbed in the powder to make a paste covering all the mould. Left it soaking in a half full sink for about 1 and a half hours. Then washed it at 60 degrees with the normal dose of ariel powder and a generous glug of white wine vinegar in the machine drawer with the ariel and voila! It has gone - completely back to normal. Feeling v proud of self! Hope this helps someone else.