The mystery missing piece appears to be this (see picture) which I found in a 996 parts catalog. Rather surprisingly, it does not appear to be shown in the similar drawing for our 986 series which I have posted above.
In any case, I will order a pair of these and will post a picture in this thread once they arrive and have been fitted.
Many thanks for the excellent detective work by all – you folks on this board really know your stuff!
Cheers - DM
