This topic has come up in the past. They were determined not to be the same as the Cambridge series.
One of the joys of buying kits from half way around the world, I guess.
I just tried my Cambridge bushings on a Roman Harvest. The lower barrel bushings fit just fine, but the upper bushings wouldn't
quite fit inside the tubes as the bushing pilot was .002" larger than the tube. If someone needed a set in a pinch, I think hitting the pilot diameters on the upper bushings with sand paper or a light touch with a file would get them to work in a substitute.
I also just measured all four of the barrel fitting ODs on a Cambridge that I turned recently and compared them to a Roman Harvest that I just received from a supplier who supports this site and they were all within ~.003" between the two.
Not trying to be argumentative, just a possible suggestion. (I have recently changed to make all my bushings TBC style and measure all of the parts first)