cover it with a wet rag or cloth and leave it until it releases, keep the cloth quite wet, it may take a while, or make a circle around it with blue tack and fill it with water. Ive never tried it but I would imagine it would work
Acetone will remove it. Many nail varnish removers are now ''acetone-free''. Most chemists should have acetone. At Boots, you'd have to ask at the pharmacy. You might even find it at Morrisons in the nail care section. But try a little on a small area, as it can discolour some laminate finishes. See...
Warm soapy water will definitely remove it.
Don't try hard, just leave a wet soapy cloth on it for some time, replacing occasionally until it comes unstuck.
Must agree about using water. Superglue sets through the moisture in air, (or on your skin!) acting as a catalyst and allowing the glue to cure. Too much water, and the glue starts to break down. May take a few hours of soaking, but at least it wouldn't cause any damage to the worktop.