Licence action by the CAA is very rare. As others have said, there is more interest in finding out what helped cause the incident and then trying to take steps to prevent it happening again. Being honest with the CAA and telling them how you came to misinterpret the chart will assist greatly in this. It could be that the third party chart suppliers will also be asked by the CAA to amend their charts if they are indeed ambiguous. In which case, your honesty will help prevent others falling in to the same trap and possibly having even worse consequences.
I think the worst they will do is put a letter on your 'file' noting that you have been offered appropriate 'guidance' to prevent you doing it again.