"I guess I still don't understand what bi-laminate lugs are because these look like normal lugs (albeit way cool semi-fancy normal!) I thought bi-laminate meant kind of "one lug on top of another.."
Bi-Laminate lugs arise when you can't get enough lugs, like when you are a post WWII builder in Europe. You also have have more demand for lugged bikes than fillet brazed.
So what do you do? Here's my rough idea of the process:
Cut flat patterns from sheet (could start with tubing too if the right ID). Shape and weld into "cylinders". Fit on frame tubes and jig. Braze, including a fillet braze at the seam where the cylinders (and underlying tubes) are mitered. End result- looks like a lugged frame with a slightly bigger fillet at the miter than you get with a normal lug. One tell tale on a BB would be no openings (or just vents) for the tubes because you started with a cylinder, tapped threads etc.
The end result looks like a Herse looks but in that case it's usually fillet over a lug. Perhap's Herse liked that look from the bi-laminate days.
This approach allows totally custom lug paterns but must have been very time consuming.
Not just British builders did this. I have a Dutch bike called a Pestmann, circa 1950 with bi-laminate lugs. I suppose it died out as lugs became more available.
Great Notch, NJ