I have 2 Guiness Bicentenary special edition stamps in the original folder dated 20th July 1959, mint condition in the envelope they were posted in. Do they have any value?

by Laura
(Somerset)

My mother won these special stamps but she tore the stamp on the envelope which marked the first day of issue. The value on the stamps is 3d and 1/3 and they are in the original cellophane packet, never opened.