Some sun tour on that competition would seem propper. Maybe some first gen cyclone???

I remember those pretty well, I wanted one badly. It's a Raleigh Competition (not Competition II), made in the Carlton factory. It should have Huret or Simplex dropouts and either full 531 db or 531 main tubes db. It came new with all French components, like a contemporary PX-10, though some had Huret derailleurs instead of Simplex. I recall that black one from late '60s or perhaps 1970. I recall Nervex lugs, but they could have been Capella - I don't think I knew the difference back then. I didn't and now don't know anything about the S/Ns. But looking at the original markings, I'm pretty sure it's a Competition from my high-school days 1970 or before. The Competitions came in just that basic black, where the Internationals and Super Courses had the deeper metallic green or copper.

They were really light.

By the time I had saved up enough, they were not being sold in my local shops. Later the Comp II's showed up, with mostly Japanese components.

The Sheldon page shows a Competition Mk II, not a Competition. It has block-letter "Raleigh" on the downtube, not script. The earlier ones (like the Super Courses) had script lettering.

Sheldon's page showed a TA 3-arm crank, and I clearly recall Stronglight cranks in the shops.

Are these differences improvements compared to the earlier model or not?

Note from a little farther down on the Serial Number scheme - confirms what we already knew:

Notes:

1. The 531DB Gran Sports built in the early 70's did not have letters in the serial number.
2. Frames built at the Ilkeston facility have serial numbers that begin with "SB".
3. The 1973 track frames begin with an "A".
4. There are several documented cases of '73 and '74 Professionals, Internationals, Competitions and RRAs with "A" serial numbers. Let the color scheme, decals and components be your guide.

I have a '73 Competition frame with a fork with problematic threading. Need to figure out a solution for it, as I'd really like to build and ride it.

Depends on your perspective. Same tubeset but racier geometry and different lugs. I had one and really liked it.

This is a Capella-lugged '73 Raleigh Competition with a few modifications.

"A few." Heh.