All things added together increase the value and cost of an item. Just as in buying a car, each accessory or add-on raises the price it is the same in collectibles. In this case a Coalport vase carries a number of marks that help increase its value.
1. the factory makers mark “Coalport” England, a crown and a date of “A. D. 1750.” (which is not the date it was made but the date of factories start)
2. title of the paintings scene
3. decorators and style numbers
4. the painting is signed by the artist
Each one of these five items adds more to the value as whole. You pay more yet receive more in value when items like this are purchased. Remember condition is number one but the add-ons are the path to more value.