Help identify this frame/fork?

[Ductape]

Recent Craigslist find. Not sure what it is yet? Fillet brazed and just unique enough one of you should know what exactly it is hidden under the 1/4 inch of paint:

 

[Ductape]

 

[Ductape]

Thanks,
T

 

[legrandefromage]

Potts -esque

Dropouts, forks, brazing - just that rear stay on your mystery frame clearly dont match.

I'm thinking 1986-7 onwards as if memory serves, those vertical drop-outs didnt appear until then (I am happy to be corrected!) as much was still based on road parts.

 

[Ductape]

Guessing 89ish from the few parts that came with it....
I wish it were a Potts, but no...