My car was OTR in 2000 with J-reg age plate a 1.4 from said J-reg donor. No cat on donor so none was req'd
When I changed to a 1.8vvc (brand new) a couple or so years later i didn't fit a cat nor was told to by anyone in officialdom. So it has been ever since and all MOTs have used BET no cat test specs.
I read cats were only mandatory 1995ish onwards. There was a few years before that of transition where some had some didn't
Page 46 of the IVA manual has a flow chart
https://assets.publishing.service.gov.u ... hicles.pdfIt depends on whether an exact match can be found for the car under test I believe here
https://assets.publishing.service.gov.u ... dition.pdfAs GTM Libra is not listed you'll end up with a non cat BET CO<3.5% and HC<1200ppm
All of this will also have a bearing on what road tax band or category you end up in I think.