Appearing at Canterbury Crown Court Heron, from Chigwell, in Essex, and Anderson, from Smethwick, in the West Midands, both denied smuggling drugs.
Chambers, also from Smethwick, admitted the charge at a hearing on Tuesday. She will be sentenced at the end of the trial. Anderson, a bank security guard, told customs officers that he had been on a three-day Easter holiday shopping trip in the south of France with the two women. He later changed his story to claim he was just acting as a taxi driver for them.
A Sony Ericsson mobile phone handset found in Heron's handbag contained text messages between her and unknown European suppliers about arranging the deal, it was said.
A Lloyds TSB bank account used by Chambers was found to have had more than 81,000 pounds put into it a month before she was stopped at Dover.
Police also found she had a Visa card in the company name of Everol Electricals. It was registered to the same address as her TSB account and had nearly 100,000 pounds cash held in it between December 2007 and March 2008.