They are not inexpensive, but they do look great.
The whole [MGB] outer sill is 90 bucks!
Zachary!
When you see the end result of the reproduction caps and the sills proper, and you have
some fabrication skills, the prices seem astronomical.
I'm not absolutely sure, but those caps are probably imported from the US, I don't think they are made in Oz

Anyhoo, unless my
weakly Lotto entry comes good, I'm not likely to be purchasing either of these parts
As for the shape of the caps, I guess after a few glasses of after banquet Saki, it seemed like a good idea at the time
As Enrique mentioned, there are some awful debris traps in the factory sill design.
It will be a fact that access holes will be cut, probably in the cabin side flat panel to allow a liberal dose of Cavity Wax.
Then I'll fit some rubber plugs in them and they will be hidden beneath the carpet.
There will also be some non original drain holes incorporated in the new sill bottom edge.
Modern cars have these if you look closely.
The hole for the jack point is a one way valve for moisture and debris.
There is a famous quote from that eminent Russian Hot Rodder, Boris Kutchacokov: -
"You can seal water
IN but you can't seal water
OUT!"
It all gets back to studying how the car is put together, where has the design gone wrong and how can I prevent a recurrence of the problem, using stealth of course
For instance, I'm making the curved section of the cap, where the guard attaches, on a smaller radius.
This will introduce an 8-10mm gap between the inner guard surface and the sill cap, easier to flush clean than the original factory "intimate contact" design.
The trailing edge of the cap is flared out to the correct radius to mate up with the centre sill section.

I have welded two square tubing sections on the bottom of the cap.
These will be drilled and tapped to accept the guard mounting fasteners which originally screwed into captive nuts inside the sill cap.