It was in the metal recycling skip at Cruachan pumped storage power station.
on the shore of Loch Awe in Argyll, 1 km from my secret underground lab.
I trawled the web for info, these were made in Japan just before the MTB explosion in the early 80s. I think most went to the states , badged as Lotus.
Several firms used the Tange aero tubing to construct bikes, Miyata, Lotus and others, most used the Shimano Ax stuff, my bike isnt the top of the range "team " model and is not double butted tubing, but to my eyes it is very well made, no dings and straight and true. Weighs about 23 lbs.
This replaces my old BSA tour de France which my son has adopted, and feels like it is from another planet.