Posted: 29/01/2013 at 23:55
Hi Leanne, the first thing to do is try and identify which type it is. There are evergreen and deciduous types of Photinia. If it has lost its leaves, it is a deciduous type and can be pruned now while it is dormant. If it is evergreen, best prune in spring or summer. The good news is that whatever type it is, you can cut it back hard if it is really overgrown and it will grow back. Always cut to an outward facing bud. Keep it in shape by trimming the new shoots when they reach the size you want. As new shoots can be damaged by frost, I would err on the side of caution and delay cutting it back until the danger of frost has passed.
If it is an evergreen one, see here: