A tree on a housing estate, with sawtooth edged simple leaes. The flowers have a large, pale leaf-like cover with small flowers underneath.

Here are my pictures:
http://www.geograph.org.uk/photo/4004031 - the tree
http://www.geograph.org.uk/photo/4004034 - the flowers, after the fruit has started to set
http://www.geograph.org.uk/photo/4004037 - the leaves, along with what looks like cherry leaf gall or Eriophyes mite gall

Any ideas?