If you go to garden centers and nurseries, you'll note they use shade cloth, so does Tropica and all aquatic plant growers.
This adjust the sunlight intensity, I use about 10% shade cloth for outdoor culture, this is about 150-200micromols at the top for where I live typically. Likely more seasonal variation in the UK for light.
So it can be used very well as long as you adjust the shading.
Frosted glass etc can be used also, metal screening in layers, inserts etc.
Adding metal screen inside the fixtures works well for hobbyists, for sunlight, the above suggestions work very well.
Regards,
Tom Barr