Disabling emitter light source reflection

Hi! First time posting, so please excuse me if this has been answered before, I’ve had a good look.

I have an emitter with a GPU sprite which can’t cast light, so I’ve added a dummy emitter to do so. The problem I’m having is that the light source casts a reflection when I just want the soft light itself in the particle system.

A fix for a similar query with light nodes is to increase the roughness but this doesn’t seem to be possible for particle lights. At least, not as far as I can see.

Do you have any suggestions for what I could try? I’d be very much appreciative.