VX engine, date of manufacture??

[gafferjim]

We've got a 16v red top, that we're putting in a kit car, unfortunately it was bought as 'spares' now we need to be able to show the DVLA the year of manufacture, or it's going to need a cat. Can anyone help me? Vauxhall themselves were about as much use as a one-legged man in an arse-kicking contest!