QSL for 50 MHz SSB contact between myself G0LGS and OH1AYQ on 22/07/1989 – It was actually my third QSO that day with Finland, but the only one I have received a QSL confirmation for.
See http://www.g8bcg.org.uk/6mukfirsts.htm for the complete list of 6m UK Firsts.
Well it was the first for a while, but I have noticed that the list (linked above) has been updated as someone else had a earlier confirmed QSO.