There’s a discussion of the tranny mount in the XJ-S with the GM400 transmission going on right now, including a couple of photos:
I’m not as familiar with the SIII mount, but it certainly seems to me a couple of parts are missing from that diagram. I suspect there should be two of the sleeve directly under the circled part. And between those two sleeves there probably should be a washer that’s kinda thick with rounded edges for sliding up and down within the rubber bushing C.30159.