Your search for "Effervescent tablet" revealed the following:

Sale price £30.40 Regular price £40.00 Sale
Sale price £36.49 Regular price £50.00 Sale
On Sale from £29.97 Regular price £33.00 Sale
On Sale from £29.97 Regular price £40.00 Sale
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Sale price £39.52 Regular price £50.00 Sale
Sale price £26.89 Regular price £40.00 Sale
Sale price £36.70 Regular price £44.00 Sale