National Grid Ref SK 147 829
The sign read "Wonder Caves" and laterly "Caves" constructed of letters 10' tall and 1'6" wide. They were made by filling a trench with local limestone, which was whitewashed annually.
The sign "Wonder Caves" was constructed in 1935 shortly after the opening of the cave complex. The sign was reduced to "Caves" sometime after 1939 at the request of the MOD. "The "Wonder" was never replaced and eventually in the late 1960's the sign was removed due to National park status.
Many Thanks to Peter C Harrison for some of the information