The quantities of gin and vermouth stated in this recipe produce a Dry Martini with a 30:1 ratio of gin to vermouth. A small amount of dilution is achieved...
Salvatore is at Donovans Bar in Browns Hotel now. The martini there certainly warrants a visit (not cheap mind!)... I think it's the best in London. Last excursion there I had the vodka one (Grey Goose) with an olive, bloody delicious! I will certainly try it at home!!