EDITED: 17/07/2018
This works for both Z3 and Z4 models (and pretty much any UK BMW too!) and all you need is the last 7 digits of your VIN number.
Updated as the original site seems to have disappeared, the current 2 alternatives that do work are:
https://www.etkbmw.com/bmw/EN/vin/decoder/online
https://www.bmwvin.com/
This works for both Z3 and Z4 models (and pretty much any UK BMW too!) and all you need is the last 7 digits of your VIN number.
Updated as the original site seems to have disappeared, the current 2 alternatives that do work are:
https://www.etkbmw.com/bmw/EN/vin/decoder/online
https://www.bmwvin.com/
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