Ha ha! Now it makes more sense!
The shed is greater than 20sq unfortunately. Not sure how big. Maybe 24sq? I have taken little interest in the shed! The guy at council said I may have to have a 8m setback for the shed from the back fence. This doesn't sound right as our fellow neighbours have their sheds 1 or 1.5m from the back. I guess only time will tell. Hopefully not another headache.
Louise