Same here. Did you find the one which ended with an opening half way up the cliff face? Im pretty sure this was the tunnel where you first descended a ladder in a well type structure, then you entered the tunnel out to the cliff.
There were quite a few tunnels at The Hope end of the fort as well.
I remember there was a cafe in Seaford in the early 80s called The Tuck Inn, every so often some wag, with a dash of paint, would convert the T to an F. As an young boy I found this hilarious. As a 50 plus adult I still find this hilarious.