Thanks very much Wintonian and Mamya. You are right - it works if you substitute an I for the second S. This would have SMALTS as SMALTI which works in the Italian sense though I still can't quite see how the whisky bit works. (FYI Wintonian, this clue was 'Southern Whisky in coloured glasses (6)')
Thanks again, I'm going to fill it in and send it off!