May I suggest that you look at punctuation in future as this is very difficult to read...
Anyway...
It sounds like the registration late of your vehicle has possibly been cloned. In simple terms this involves nothing more than somebody obtaining a set of plates bearing your registration and fitting them to a similar vehicle.
So I can see that it seems that the crash occurred in June 2023 and you sold it in October 2023. Th that end, find out from the insurance company what name and address was given to the insurers.
Ask if any pictures of the occupants of the vehicles were taken at the scene.
In damage only crashes, the statute of limitation is 6 years, which means that the third party has 6 years from date of crash to report it. The longer someone goes before claiming, the less likely that this is a genuine claim, so ask the insurance company why it has taken so long for this claim to be reported? I would love to know what their response is.
If this is also a genuine crash for cash scam, then the Police also need to be notified along with the Insurance Fraud Bureau for further investigation by them.
Insurance companies are a law onto themselves. Do you have anyway of proving once and for all to the insurance company that you were at home and not in London at the time of the alleged incident?
Lastly, consider contacting the Motor Insurance Ombudsman and speak to them about your treatment by Direct Line. The Ombudsman is the overseer and governing body of all UK insurance companies.
Insurance – Financial Ombudsman service