Hello Bee. What you describe as your "mutterings" are never boring - quite the reverse. You are right about OS maps but where possible nothing beats a site visit with the Mark 1 human eyeball, even after the demolition men have been in. My son and I are ardent amateur industrial archaeologists (fancy term for two blokes who like ferreting round old mills factories mines and railways) and over the years we have stumbled across some fascinating bits and pieces that have survived unrecognised and unmapped (like the remains of a Newcomen atmospheric engine at the site of a long demolished Warwickshire brick/ cement factory, fencing along ex-GWR branch lines manufactured from lengths of broad gauge bridge rail, most of the component parts of a steam powered rope hauled waggonway system at a long abandoned Derbyshire limestone quarry and even a WWII German Jumo lightweight diesel aero engine from a bomber shot down in 1939 on a Norfolk beach). It is astonishing what survives out there if you know where to look. When I eventually manage to retire I have every intention of subjecting any accessible parts of the L&M to minute scrutiny to see just what now remains.
Keep up the mutterings, please
threelink