GeoGraph - photograph every grid square

I first went for a holiday on this section of the Trent and Mersey Canal in Stoke in 1965 as an 8 year old. I had remembered that the top lock had a wooden cover over it. When I next went there on holiday in 2004 I was 'annoyed' to find that there was no cover over the lock and thought that my memory had failed me after 39 years.... until I saw this photograph at the side of the lock - there had indeed been one, but it was removed as it had gone rotten several years earlier!