Free Traffic Legal Advice

Scrapped car and received an email from DVLA as the scrap service themselves had informed them as confirmation of sale. They then received a PCN a few hours later and the DVLA gave the council my information as the registered owner however I wasn't the owner at the time. I sent the email and the time of the email from the DVLA as a challenge but that was rejected. I have to appeal with London tribunals but I am at a loss as to what to use as evidence as the email was rejected? Thank you.