Posted: 01/04/2014 at 08:14
Star gaze lily is right, it's a Prunus. The glossy bark of one of the stems indicates it's Prunus serrula. http://apps.rhs.org.uk/plantselector/plant?plantid=1551
It'll grow very wide, if you let it. Should you want to prune it, don't take out stems that are over 8 cm in diameter, as these will start to rot away quite easily. Prunus' should be pruned in late Summer to prevent Silver Leaf.