A highlight was a magnificent flight of locks, from memory somewhere in N. Northamptonshire, where we spent much of one afternoon working up and and over a hill. .
Foxton Locks?
That's it! thanks Richard.
https://www.google.com.au/search?q=foxton+locks&client=firefox-b&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiU4tPHjuPMAhWJmpQKHRtrC8AQ_AUICCgC&biw=1280&bih=558#tbm=isch&tbs=rimg%3ACeH5URcbNw0uIjhuVUrmkNivp5JgWUcLVPF1GzTkzz9S27YPi4jN4S_1iPDK7OBOKjxSj9IDC3nZt1F8UutyxWYAtNyoSCW5VSuaQ2K-nEdUk5uah1qKuKhIJkmBZRwtU8XUR7FwUGW0bLowqEgkbNOTPP1LbthEgRxWDLAQHqSoSCQ-LiM3hL-I8ETfNo_1X8IGmYKhIJMrs4E4qPFKMRGoDezoxW4cYqEgn0gMLedm3UXxHikiVGBmbd9SoSCRS63LFZgC03EcT-iITt9pxI&q=foxton%20locks&imgrc=kmBZRwtU8XUwBM%3A
