Short answer
Choose cloth for the places and seasons where you expect to wear these womenswear coats. Ask the tailor about fibre, weight, weave and care for the specific options; a city's name alone does not determine the right cloth.
Double-faced wool–cashmere for northern winters, weighted crepe and bonded wools for the shoulder seasons, belted or open per the brief.
A London December commission is a chance to plan the year: a winter flannel now, a Black-Tie review before the season, and a summer cloth noted in the Fit Passport for the spring route.
The full cloth books span fresh open weaves through four-season high-twist to winter flannels and cashmere blends. Bring the tailor your calendar; the shortlist comes back two or three cloths wide.
The itinerary is a proposal: months are planned, dates and venues confirmed individually. Final quotations are confirmed in writing before you commit.