Is there any markings on the box? Harrods, as well as other finer stores, sold them at one point. That could help the price some...but the boxed PASTRY FORKS (correct term for your set) that you have are very common in the US and England.
Pie forks are typically 6 - 7 1/2" in length. Yours, if I am correct are less than 5" (eyeballing it).
We have a large collection of antique pie forks that we have accumulated over the past 30 years is the only reason I know a little on this subject.
Search "boxed pastry forks" and you will see what I mean.