I found a 1960 bike on Classic Lightweights s/n 27338, so mine (27250) looks to be 1959/60 and looks to be a Hurricane: Zephyr and Cyclone had wrapover seat stays; Monsoon didn't have pump pegs or a lamp bracket. Intriguingly the Hurricane was available (up to 1959) in a fixed gear variant: the DTS bosses and gear hanger look unused. Being as all the components (save for the saddle, stem, tyres and tape) are as listed in the catalogue, or at least period, I'm now fairly convinced that this left the shop as a fixed gear rather than being converted. A couple of things that don't quite tie-in though: now the wheels are off, I have confirmed that it has Campag dropouts and not Agrati; my pump pegs are on the seat tube and the '58 had them on the down tube and by '60/'61 they were on the top tube. Other discoveries are a Villiers lockring, GB bars and a Williams chainset. Could the mudguards be original? The '58 catalogue describes them as being of "celluloid": this is early plastic? More pics here.