26lb 😯 for a singlespeed.

I'm after a second cross bike for winter and I have been looking at singlespeed specific frames only, with a build weight of about 17/19lb. But at £499 it's a good value hack.
Things I would ditch right away would be the brakes for Frogglegs and the chainset for a 36t Raceface set up. But is it that the frames a biffer or is it the sum of it's parts?

520 tubing is no lightweight.Not to be compared with better reynolds tubing

I think you would need some very expensive parts on it to get it down to 17/19lbs. It is a good frame for the money, but it does come as a complete bike for £500 afterall.

Even with singlespeed I'd expect sub-19lbs to be a reasonably pricey build. My Dave Hinde M3, which is a 3lbs frame, with RC31s, Speed King Supersonics, 1500g American Classic wheels, carbon bars and post and 200g Litespeed saddle wasn't much under 19lbs when run as a singlespeed.

I was intending to build a Traitor or Singular, but like you say it's a complete bike for frame money