V12 rear transmission mount

Hi, I was replacing my gearbox oil and noticed a piece of the transmission mount bush falling out of the gap between the gearbox support plate and large washer. I undid the large nut, removed the washer and the rest of the bush fell out, having disintegrated. Along with the bush came 3 spacers, 2 x C30157 and 1 x C29011. The parts manual only shows 1 X C30157, so I am struggling to understand why there was 2. Can any one help, and if there are supposed to be the 3 parts, what sequence do they go on the pin? I can’t understand what C29011 achieves.

Yep, had me scratching my head for a while, as the parts manual was useless!
Sequence of assembly; the C30157 slides into C30159, followed by C29011 then the second C30157.

The degraded parts ( 2xC12335 and 1xC30159 are still available) but with superceded numbers ( SNG B ).