Complex sentence: Sadly, many people are unaware that the FHBVC (Federation of Historic British Vehicle Clubs) tested and approved lead replacement fuel additives, that work out at only a couple of pence a litre.
Split into simpler sentences: Sadly, many people are unaware that the FHBVC (Federation of Historic British Vehicle Clubs) tested and approved lead replacement fuel additives do exist. These work out at only a couple of pence a litre.