So what we have on DNA is limited to hair strand evidence from the red Ford Sierra, potentially connected to SC. Plus, more recently, a fingerprint of unknown provenance found on the rear view mirror in the white Ford Fiesta driven by SL, being subjected to more advanced forensic examination. Neither has yielded any definitive evidence yet.
How did Berry-Dee get his facts mixed up about SL's DNA found in the red Sierra?
I did read somewhere that forensic aspects of the case had been debated between police and the CPS at some point after 2003 in the context of charging JC although I cannot pinpoint the date or source. This does suggest the police have latched onto something although quite what and whether it involves a car is uncertain.
Since DV published his unsupported nonsense, this thread has been driven at times by wild postulation which has made it difficult to separate fact from fiction.