"Gaspipe tubing, crude lugwork and second-line Japanese accessories".
'It's impossible to tell for sure in this lo-res shot, but that could be a Reynolds decal'
Definitely not 531 or anything close - otherwise I wouldn't taken a hack saw to the frame however bad the lug work.
Some type of plain gauge Hi-Ten steel as I recall.
Still got a couple of bits of it in the shed in the same light metallic green as in the pix - but no decal/s on any of it.
Ian briggs - LUTON, Bedfordshire UK