I need beverage stock auditors

We need reliable people to carry out beverage audits in central london. The work involves counting bottles of spirits, wine, beer and weighing open bottles in hotels, bars and restaurants.
Using a mobile phone app we track the amount counted and enter into a windows based programme.
Must be fit, able to use windows and a smart phone and happy to work unsociable hours. Ongoing work, initially 1 day a week but growing over the following weeks.