Modern paperweights are really tricky to value. Often a paperweight will be manufactured in a limited edition, but the original retail value may bear no relation to the re-sale value.
The Harrods name will carry some Kudos but your paperweight is more of a gift weight than a limited edition collectable.
If you intend to keep the weight and enjoy its aesthetic appearance then the value is of no real consequence.
I will now extricate the splinters from my glutæus maximus having spent a little too long sitting on the fence!!!