Unite general secretary election challenger Simon Dubbins has publicly challenged incumbent Sharon Graham to stop hiding from him and debate him directly. The explosive challenge comes after Graham repeatedly sent proxies rather than face Dubbins in person, to the disgust of members — even close allies. While Dubbins attended every hustings to which he was invited, according to Unite insiders Graham didn’t attend a single hustings: As a result, Dubbins gained big wins in huge Unite sectors Graham would previously have considered sewn up tightly, including defence, air travel and construction. Dubbins is also set to win Unite’s ‘Community’ section —…