I doubt it's Araneus diadematus which has a 'cross' of white spots on it's back.
http://bugguide.net/node/view/...
There are other spiders which look similar, it could be an Araneus species or another in the same family Araneidae.
Reminds me most of Thomisidae, Xysticus sp.
https://www.google.co.uk/searc...
