Try contacting a Burberry outlet or visiting one if you live near one...it's your safest bet, buying online is so questionable with all the fakes! There are Burberry outlets outside Chicago, Boston, west of D.C., Orlando, etc....good luck!!!
I notice that you are in San Francisco. I am bay area native The only Burberry outlet I know of out west is at the Primm outlets on the Nevada/ California border. Its about a 30 mile drive from Las Vegas. I got my Burberry umbrella there but it was the travel size. If I remember ( it was a while ago 2002) they had all types of umbrellas. Here is their # 702 874-2244. Or... Fashion Outlet Las Vegas good luck!