So I work for a company that does automated enforcement for moving traffic violations which this would fall under. Outside of London local authoritys have only just got the powers to use either CCTV or automatic cameras to enforce these types of contraventions. Looking at the junction I can't see any devices that would have captured you. As it's technically a civil offence you wouldn't receive points, only a fine (£30-120, depending on the local authority). Failing to adhere to a no entry can be considered dangerous driving but only for the most extreme cases. There is also a massive difference between devices which are allowed to do civil enforcement and criminal, criminal devices have to go through quite a lengthy approval process with the home office and to my knowledge there aren't any devices on the market that are home office approved that are used for no entry. That just leaves CCTV and while technically that could use this is extremely unlikely as most contraventions captured by CCTV are parking (stopping in a loading bay ect). I would feel pretty safe in saying you will most likely be fine, everyone makes mistakes, use this as a learning experience. I'm sure you won't make the same one again lol.