We have had fairy rings in on our lawn this autumn and there are now several brown rings left by this fungus, is there an effective cure?

There is no cure, at least not to the general public.

The only other suggested treatment for the amateur, is to spike the area of brown grass, and water well with a washing up liquid and water mixture.

The dead areas are caused by the water repellency of the soil after fungal activity and the thorough wetting may help to overcome this effect.

Repeat as necessary.