An Inspector's decision may be challenged in the High Court within 6 weeks on the basis they have erred in law. For example, if there was a mistake in legal procedures or some vital information was ignored.
To bring a judicial review claim, the person bringing the claim must have “standing”. This means that the person (including a group or company) has a sufficient interest in the matter. A group will have sufficient interest if it represents the interests of individuals who are directly affected by a decision.
If the High Court upholds the challenge, a different Inspector will reconsider the appeal avoiding the mistake, but it is possible the outcome will be the same. Taking a case to judicial review is an expensive process and, if you are unsuccessful costs could well be awarded against you, so you are strongly recommended to seek legal advice if you are considering this course of action.