Can I prune Photinia Red Robin

The best time to prune them is when the new red growth has turned green which should be soon. I give my hedge a light trim each year and that helps it remain nice and bushy. But did you mean cut it down to 30cm from the ground ( I expect it will survive but sounds a bit severe ) or did you mean trim off 30cm lengths from the top which sounds fine.

Thanks for the answer. I have now pruned the 2 shrubs I have, by around 60cm's and they are looking much better. Claire.