Sorry if it was unclear
@conny. The light has been fitted and I used my old approach of gritting my teeth whilst drilling the ceiling board. If it's hollow, I will use a plug and if it hits timber, I will screw straight into this. As I said, my experiences thus far have all been around lighter light fittings and hence the strength of a timber fix hasn't always been necessary. My main concern was the risk of hitting a cable. Hence the need for this post.