I just went thru this with the Red Car PS on a BBC 1968.
I ordered replacement clamps from a vendor and finally got around to trying to use them they WERE undersize and would NOT slip onto the HOSE!
These Repops are made in Europe and go by mm sizing and I had to figure out art numbers and source for a sizing increase from 15mm to 17mm sizing to get them to fit.
I like the USA vintage clamps