Alongside the River Colne and the M1 link road Bushey/Watford borders close to Euston mainline railway track.
Yes there were many but long gone A few more on the same river but a few miles further south Anti Tank Cubes, River Colne Bridge Crossing, Tolpits Lane/Moor Lane, Moor Park, Herts and very close to the above Anti Tank Cubes, Withey Beds, Moor Park, Herts