Can anyone recommend a reasonably priced florist who can do wedding flowers in the Surrey area?

why not talk to the florist you can find with the best prices and ask them what they can do to reduce costs. Maybe you are asking for orchids or roses or something expensive or out of season. Changing to a cheaper flower could make the difference. Maybe making your bridesmaids bouquets smaller would make a huge difference. Maybe you could do non-floral centerpieces, or something simple that you could arrange yourself (like a few wildflowers in a mason jar or a single flower floating in a vase).