Sold my car, then had a PCN served on me (UK residents please)?

12 days after I sold my car, I was served with a Penalty Charge Notice for a traffic offence that the new owner had committed in London, I tried to contact Ealing council to explain I was not the owner or driver of this vehicle, I phoned then sent letters to no avail, so I wrote to DVLA for a letter confirming I had sold vehicle, but in 9 months they had not replied, meanwhile the £60 fine has escalated to £202 and Court application for Bailiffs is about to take place, after receiving threat of Bailiffs I wrote complaining to CEO of DVLA about request, they denied receiving it but did send a letter confirming my date of selling my car. before sending me threat of bailiff application the court did send me an 'out of time/late filing' form which I filled in, but did not at that time have any written proof of the date of sale to send to court.

More recently I managed to find a link to complain to Ealing council, the site really is tough to navigate, and they sent me a reply email stating I have no choice but to file a 'late/out of time' form asking the court to waive my fine, but the mind boggles because to achieve this I have to get the form witnessed and sworn before a solicitor or other legally qualified person, but the real crunch is there are only three options to tick on the court paper and non of them applies to me,

I've visited the Citizen's Advice Bureau, but they are really stumped in what I should do, because they agree there is no option on court paper that fits.