No.
But I seem some ww11 pil boxes recently. Made from thick concrete.
They were manned and cables ran down to the local train bridge ready to blow it when the jerries came.
E. Sussex is covered with pillboxes - my Great-Uncle built some of them. And apparently there was a lot of undercover guys ready to sabotage etc. People with reserved occupations and Dad's Army too . So the bungling "army" of the old was a bit of our propaganda