 Complete the following phrase:  After commissioning, Sandown carried out an extensive programme of trials, and was not fully operational until December 1992, having suffered problems with her sonar outfit. She participated in a number of operations in support of the British fleet, including operating as part of a NATO-led operation between 12 June - 26 August 1999, along with the Hunt class Mine countermeasure vessel and the survey ship . The operation was intended to clear the Adriatic of bombs jettisoned during the 