County court appeals have to be started within 21 days of you being notified of the review decision. The 21 days start from the day that you receive the letter, not the date printed on the letter.
In some circumstances, it is possible to begin an appeal after the 21 day time limit has passed, but this is unusual. It is normally only allowed if you have a very good reason for not applying sooner. This might be because you have been seriously ill or did not receive the council’s decision letter. Get advice immediately if you need to make a late appeal.
If 8 weeks has passed since you asked for a review and you have not received any review decision from the council, you can appeal to the county court to try and force a decision. This appeal must be brought within 21 days of the date that you should have had the review decision. If this applies to you, get urgent advice as you will need someone to help you with this.