In most UK independant handling agents (don't mention the 'S' word!), dispatchers have very little to do with flight Ops. They are responsible for the tunaround of the Aircraft. This usually involves being out on the ramp supervising loading of baggage and cargo, cleaning of the A/C, catering and boarding of passengers. Office based people take care of flight plans and other flightdeck paperwork such the loadsheet.
Most ground Handling in the Uk is performed by independants such as Aviance, GHI etc.