very early (like '40s, maybe '50s) whatever it is...could be a Holdsworth, but as you say those lugs don't correspond to the published patterns in the catalogs. Could be one of the "other" brands associated with Holdsworth: Claud Butler, Freddie Grubbs or one of the Holdsworth builders who might have freelanced (Bill Hurlow, Owen Bryers...there may be others). Any sign of holes (might be filled-in) for a headbadge: most of these brands would have used a metal badge. The dropouts are similar to those on Claud Butlers, but others may have used them too.
This is one for Hillary Stone or Norris Lockley to solve!