I am looking for a better ID on this chainset.

It looks to be 116 bcd, and has Williams chainring bolts. Actually it looks like the whole set could have been Williams, but I think they used 6 3/4 arms with 116 bcd, these are 6 1/2.

It came off a 61 Lenton Grand Prix, with a 3 speed hub.

Was this an optional chainring for folks that didn’t want deraileaur gears? Is it a Track chainset? What model would it have come with normally?