I wouldn't touch it with a bargepole, given that while you don't need beautiful 'stacked coins' to have a good weld there are a few problems...
-Looks like someone with some skill did the front triangle, then they got a monkey to do the rest.
-The front shielding was inadequate, given the well past 'pale straw' colour.
-Weld discolouration suggests it's probably not been back-purged.
-Also the white plume around the weld suggests that it wasn't cleaned well before welding.
-Oh and also doesn't look like there's any seat clamp slot, brake mounts or cable fittings.
-An unfinished project, so the headtube, seattube and BB would probably need reaming, facing tapping etc, too
Just about worth £99 for the scrap tubing though, not cheap those oval chainstays and tapered seatstays, at least £40 each.
All the best,
Pause, take a breath and ask yourself: "What would Rastamouse