When a plan is found sound it then is for the planning authority to determine whether and when to adopt it. Such a decision must be taken by the full council, not a committee.
After the decision has been made to adopt a plan there is a six week period where challenges to this decision can be made to the High Court. Court challenges are very complex and costly and so this should only be undertaken where it is considered that there has been a serious failing in the process of preparing the plan. If you feel that there are grounds to challenge the decision to adopt the plan then it is strongly recommended that you seek professional legal advice. If you cannot afford to pay for legal advice then you may be eligible for Legal Aid.
The Planning Practice Guidance sets out that most plans are likely to need review in whole or part every five years, for example as national policy and economic circumstances change, so should the plan.