In my case, the chassis number is only to be found on the brass plate on the bulkhead (on my car “Z11375”).  There are two sequences of engine number.  The first (non model-specific) number is on the brass plate aforementioned (“3123”), and the second, (model-specific) number, on the top of the nearside forward engine bearer (“35Z/163”).

Apologies for the slow reply, I must look at the forum more often!