The jury at Lewis Crown court heard how Lauren Bishop, Michael Clark and Edward Phillips, met up after and celebrated by buying and drinking alcohol on the seafront.
CCTV from the Londis store nearby showed Phillips and Clarke laughing and joking shortly after carrying what the court heard was a brutal, vicious and horrific attack.
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Holly has the latest forecast for the east of the region.
Holly has the latest forecast for the west of the region.
People could suffer vision loss or infection from the lenses, which are often sold illegally online, in shops and on market stalls.