A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk 05.01.2016, accepted for publication in Coastal Engineering 109(3), 20-41 (doi:10.1016/j.coastaleng.2015