Do I have have to pay for wedding dress alterations?

I went to get measured for my wedding dress in December, and tried on the gown in the shop with my bridal shoes. One lady in the shop suggested it just needed to be an inch longer whereas the owner advised two inches. So my dress was ordered in two inches longer. I tried it on today and it is an inch too long, and as there are five layers they said it will cost me up to £90 to alter. Why should I have to pay when it is their mistake that it was ordered in the wrong length, especially when one assistant said only needed an extra inch. Do I have any rights?