I do not know what is available in the UK, but if you get a real nasty buildup, there are cleaners like Zap, CLR, Lime Out, Simple Green etc etc etc.
Or, you can use Powdered Water Softener and water. 1 gal of water to one teaspoon of water softener. Then use a clean cloth and undiluted white vinegar as a wipe down, not to soak. Then rinse under running water