Addendum March 3, 2024: - Hold the presses!
It turns out the first part of the page posted in 2015 is wrong.
The large end ID is smaller at 1-5/8".
The small end ID is larger at 1/2".
And the first picture is also wrong, for the same reasons.
Information below the first horizontal rule is correct.

On 4/22/2015, Peter Black in Australia wrote:
"Attached is a picture of what is the  correct  boot available out of Australia.
Boot has what I have been told elsewhere is the correct number of ribs, 11.
Overall length is, 6-1/4"
Large ID is, 1-14/16"
Small ID is 7/16"
Flat area on both ends to accommodate clamp width is 11/32" wide.

At first glance the Moss clamps appear to not fit on the boots. But when the boot is installed the rubber ends stretch into place, and the Moss clamps work well.

"The gentleman who supplies this part is in suburban Victoria, second generation family business and knows his apples. A lovely man to deal with.
email: jwclassicparts@yahoo.com.au
+613 97626025 Office
+613 97622958 Fax

Jim Withers (JW Classic Parts)
PO Box 360
Kilsyth Vic. 3137
Australia.

On Feb 26, 2019, Don Tremblay in Rutland, northeast USA wrote:
"Here are a few pictures of a set of OEM factory boots removed from their packaging after 55+ years of storage. They look like they were just made still in perfect condition"!

On August 1, 2022, Peter Ryle in Peterborough, CAMBS, UK wrote:
"Sports and Classics in the US sell original spec/quality rubber ones". -- Stock No RP9305
www.sportsandclassics.com/..../aaa1682-oe-style-mg-mga-steering-rack-boot-pair

Addendum March 3, 2024:
Here is a nice boot from Scarborough Faire. Thick vinyl that looks like rubber, very tough and durable, might last a life time. Correct 1/2" ID on the small end, and 1-9/16" ID on the large end. Groove width on both ends is 5/16", perfect with original 1/4" wide clips (until proven different).

Clip Large ACA6030 BMK924

Clip Small ACA5118 3H2963
The clips shown are from Moss Motors, USA.
They are okay, if you buy the ones noted as "original type".

More information for these specific rubber seal part numbers here:
130801 or AAA1682