Gretsch Synchromatic 160 acoustic guitar expected to sell for as much as £120,000, as star lot in auction of items owned by late personal assistant Siobhan BaileyOne of the most iconic items in George Michael’s career, the acoustic guitar he energetically strummed in the video for 1987’s Faith, is going up for auction.The guitar, a Gretsch Synchromatic 160 with a sunburst finish to the body, has an estimated sale price of £60,000-£120,000. It comes with a case featuring the words Rockabil