Answered my own question! Pretty stupid...but I hate testing geoprocessing from within ArcMap because the forms are unbelievably slow, within ArcCatalogue they are fine, but try to open a model and run the same from ArcMap, then its 2min wait before it opens and takes forever to begin. But i just used copy features which i stupidly overlooked and rely on the inbuilt functionality that if there's a selection, its used for the output.
Any one knows why the forms etc. take so long to load etc. within ArcMap then that would be awesome.