Can you help to identify these frames, bikes or parts?

Could anyone shed some light on the maker/builder of this frame before it goes to the sprayers?

Steel (obviously) and light.
Has been poorly painted and Bob Jackson's (JRJ) confirmed it's not one of theirs.

Frame no. 881 only found on rear offside dropout;Nervex stamped on b/b with fancy lugs; drilled for front brake only; no rivet holes for headbadge on headtube;round profile forks.

Any info appreciated.

That saddle clamp is on wrong way round, no?