Geograph - photograph every grid square

Two unusual WW2 defences overlooking Gallions Reach are slowly sliding down towards the river. Next to each other on the banks of the Thames are these variants. The pillbox behind is double-level with steps inside. It is covered in pitch. The pillbox in the foreground is a thin-walled brick variant, presumably a machine-gun emplacement. The area is littered with rubbish and debris including anti-tank concrete and rusting poles.

Both defences are in poor condition and badly vandalised. I had to walk a long way to find them and clamber down a very slippery river-bank to investigate these. Both appear to be unlisted by 'Defence of Britain'. If you have any more information about them, please email me. I have visited many pillboxes and never seen ones like this.