I planted a fatsia last year which appeared in good condition. Since it started to establish it is beginning to look more like a “Swiss cheese plant” rather than a Fatsia. Why would this have happened and can I do anything to reverse the trend.
By a swiss cheese plant, I presume you mean holes. These may be made by snails, which it will outgrow, or if the centre of the leaves looks tattered, this could be caused by capsid bugs, which feed on the young leaves when small and the holes expand. Again, it is doing well in good soil, it will grow out eventually.