A statement on the Chessington World of Adventures' website said:
"Due to unforeseen circumstances, Chessington will be closed today.
"If you had tickets booked for today they will be valid for another day in the future."
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Led by Quo frontman Francis Rossi, Parfitt's band mate for 50 years, the group's current line-up joined mourners at Woking Crematorium.
Currently the Ealing Council has a huge shortage of suitable space and sees these steel well insulated boxes as a cheaper alternative.
Staff at Envirowaste in Leyton say the medal may have been left within a piece of furniture and thrown away accidentally.