With the Met Office recording the hottest-ever day in May, it's no surprise that Britons are desperately hunting for new ways to stay cool. And the ChillPill, a brand-new type of fan that emerged from the R&D laboratory at SharkNinja back in March, seems to have been a beneficiary of the sweltering heatwave gripping the UK. This nifty handheld fan costs £130, but has sold-out in four of the available six colourways in the Shark online store.At t…