If your washbasin is blocked in Swindon, Gloucestershire, the first step would be to use a plunger. Turn off the water supply and place the rubber cup of your plunger over the plughole so that it has an airtight seal. Push down on top of it firmly several times releasing each time then relatively quickly pull up again pumping continuously until any blockage from within should dissolve or pop free enabling you to unblock sink naturally with pressure alone! If this does not work for you another method which can often prove successful is mixing equal parts boiling water and baking soda together before pouring into drain letting sit overnight followed by adding some white vinegar afterward allowing chemical reaction between two ingredients soften stubborn grease build-ups further breaking them apart flushing away as liquid dissolved scum filled solids move through property's plumbing system go full circle exiting main sewer line out near front green waste! You could also try using bicarbonate soda combined with just hot tap either one separately make sure all drains stay clear backed up leaving nothing clogging pipes causing drainage issues ever again-Good luck fixing issue!"