Eric Clapton's ballad 'Wonderful Tonight' is one of the great love songs of our time. It was written on a modified 1974 Martin 000-28 acoustic which, since the late 90s, has been in the hands of a private collector. Now, as the guitar comes up for sale once again at Bonhams auction house in London on 12 June, we took the chance to take a quick tour round the unique features of this historic guitar, from its unique bridge embellished with snowflake inlays to its unique marks of use in Clapton's hands.