The DVLA may have only given you a temporary licence if they have any medical concerns regarding your fitness to drive, it means that they can monitor it in 12 months when you renew your licence with them.
The normal period for disclosure is 5 years, however I would be careful when answering any questions from the insurance company. Even after the 5 years have passed they may try to get around it by asking if you have been disqualified within the last 5 years. If you fail to disclose that you have been then they will likely try to void your policy, and you are then looking at a protracted argument with them about whether you were covered or not.