Hi, I think that you might need to add some ericaceous compost to boost your skimmia. The leaves may have suffered in the sun. Skimmia prefers some shade. Could it be that your plant has been out in full sun during the hot summer?

it looks as if it needs a good general feed. it doesn't need ericaceous compost as it isn't fussy at all. mine grow on chalk. though better with some light shade.

has it been in the same pot for a few years? perhaps a new bigger pot with fresh compost/soil and a general slow release feed is all it needs.

it has formed new flower buds for next spring so it isn't that unhappy. you will find it drops the odd leaf throughout the year, this is normal.

Many thanks Chickweed and Seaburngirl. That's very helpful. I clearly need to move it to somewhere more shaded, as its current position gets a lot of sun. It has only been in its pot for a couple of years after I moved it from a place where the soil is rather poor, hoping it would improve. I will feed it soon.