It still leaves the question of who gave them your details.
Unless I accidentally misplaced a document of some kind with my details on it that a stranger came across (and as far as I'm aware, all I was carrying was a bag of clothes), it's a complete mystery to me.
Could be anyone these days. Identity thieves obtain personal information from a variety of different sources, for many different reasons. Theres pickpocketing, stealing personal correspondence from post office vehicles, out of mailbags etc, thrown away junk mail from recycling bins, plus a lot of other possibilities. Who can say where they might have got your name and address from ? In this so called information age there are those who say there is nothing more insecure known to mankind than a computer. The possibilities are almost endless. There are probably lots of people in different places who have or who have had access to a record of your name and address, and all it would take is for one such person to keep a note of it for future dishonest purposes.
It reminds me of the proprietor of a garage a few years ago, who kept written records of the names of all his customers who paid over the telephone for work done on their cars, together with the details of the debit or credit cards used for the transactions. Then, just before he disappeared owing many people money, he did multiple cardholder not present transactions using these card details, with all the money from this going into his business bank account. By the time the customers realized and reported this to their banks and card issuers, the guy had emptied the account and done a runner. As far as I know, no-one's caught up with him yet either, although Im sure several people including the police and some of his ex employees who are owed wages, are still looking. Now that's just one devious person that I know about. There are probably thousands of people like him all around the country, blagging the system in different ways for their own ends.
This con merchant conned the banks and credit card companies, not the actual customers, although obviously it doesn't seem like that at the time when things like this happen.
Whoever gave your name to Southeastern has effectively conned them, not you, it's just a shame that it always seems to be the honest law abiding people who end up having to spend time sorting out the mess afterwards.
For you to be convicted in court of whatever it could be that they 'may' suspect you of, the person who alleges they spoke to you at the time would have to be able to positively identify you in court under oath, as the person who was spoken to, which they obviously cannot truthfully do because you were never spoken to. If Southeastern wanted to pursue the matter, it would be for them to identify the actual person who gave your details, and prosecute them, if they can be found.